If f(X)= 2x/1+x then show that f(tanθ) = sin 2θ.
If f(x) = 1/1-x then show that f [f{f(x)}] = x.
If f(x) = 1/2x+1 and then prove that f{(x)} = 2x+1/2x+3 , when it is given that
If f(x)= x+1/x-1 then show that f{f(x)} = x.
If f(x) = x-1/x+1 then show that
(i) f(1/x) = – f(X)
(ii) f(-1/x)=-1/f(x)
If f(x) = x2 – 3x + 4 and f(x) = f(2x + 1), find the values of x.
Answer : Given: f(x) = x2 – 3x + 4----- (1) and f(x) = f(2x + 1) Need to Find: Value of x Replacing x by (2x + 1) in equation (1) we get, f(2x + 1) = (2x + 1)2 – 3(2x + 1) +...
The function is the formula to convert x °C to Fahrenheit units. Find
(i) F(0),
(ii) F(–10),
(iii) The value of x when f(x) = 212. Interpret the result in each case.
Answer : Given: (i) To find: (i) F(0) Substituting the value of x = 0 in eq. (i), we get ⇒ F(0) = 32 It means 0° C = 32° F To find: (ii) F(-10) Substituting the value of x = -10 in eq. (i), we get...
Solve for x and y :
$\frac{x}{a}+\frac{y}{b}=\mathrm{a}+\mathrm{b}$,
$\frac{x}{a^{2}}+\frac{y}{b^{2}}=2$
Solution: The given equations are $\begin{array}{l} \frac{x}{a}+\frac{y}{b}=\mathrm{a}+\mathrm{b}\dots \dots(i) \\ \frac{x}{a^{2}}+\frac{y}{b^{2}}=2\dots \dots(ii) \end{array}$ Multiplying...
Solve for x and y :
$a^{2} x+b^{2} y=c^{2}$,
$b^{2} x+a^{2} y=d^{2}$
Solution: The given equations are $\begin{array}{l} a^{2} x+b^{2} y=c^{2}\dots \dots (i) \\ b^{2} x+a^{2} y=d^{2} \dots \dots(ii) \end{array}$ Multiplying equation(i) by $\mathrm{a}^{2}$ and...
Solve for x and y :
$\mathrm{x}+\mathrm{y}=\mathrm{a}+\mathrm{b}$,
$\mathrm{ax}-\mathrm{by}=\mathrm{a}^{2}-\mathrm{b}^{2}$
Solution: The given equations are $\begin{array}{l} \mathrm{x}+\mathrm{y}=\mathrm{a}+\mathrm{b} \quad\{\ldots \ldots(i) \\ \mathrm{ax}-\mathrm{by}=\mathrm{a}^{2}-\mathrm{b}^{2}+\ldots \ldots(ii) \\...
Solve for x and y :
$\frac{b x}{a}+\frac{a y}{b}=\mathrm{a}^{2}+\mathrm{b}^{2}$,
$\mathrm{x}+\mathrm{y}=2 \mathrm{ab}$
Solution: The given eq. are: $\frac{b x}{a}+\frac{a y}{b}=\mathrm{a}^{2}+\mathrm{b}^{2}$ By taking LCM, we obtain: $\begin{array}{l} \frac{b^{2} x+a^{2} y}{a b}=a^{2}+b^{2} \\ \Rightarrow b^{2}...
Solve for x and y :
$\frac{b x}{a}-\frac{a y}{b}+\mathrm{a}+\mathrm{b}=0$,
$\mathrm{~b} \mathrm{x}-\mathrm{ay}+2 \mathrm{ab}=0$
Solution: The given equations are: $\frac{b x}{a}-\frac{a y}{b}+a+b=0$ By taking LCM, we obtain: $b^{2} x-a^{2} y=-a^{2} b-b^{2} a\dots \dots(i)$ and $b x-a y+2 a b=0$ $b x-a y=-2 a b\dots...
Solve for x and y:
$a x-b y=a^{2}+b^{2}$,
$x+y=2 a$
Solution: The given equations are $\begin{array}{l} a x-b y=a^{2}+b^{2}\dots \dots(i) \\ x+y=2 a\dots \dots(ii) \end{array}$ From equation(ii) $y=2 a-x$ Substituting $\mathrm{y}=2...
Solve for x and y :
$6(a x+b y)=3 a+2 b$
$6(b x-a y)=3 b-2 a$
Solution: The given equations are $\begin{array}{l} 6(a x+b y)=3 a+2 b \\ \Rightarrow 6 a x+6 b y=3 a+2 b\dots \dots(i) \end{array}$ and $6(b x-a y)=3 b-2 a$ $\Rightarrow 6 b x-6 a y=3 b-2 a\dots...
Solve for x and y :
$\frac{x}{a}-\frac{y}{b}=0$,
$a x+b y=a^{2}+b^{2}$
Solution: The given eq. can be written as $\begin{array}{l} \frac{x}{a}-\frac{y}{b}=0\dots \dots(i) \\ a x+b y-u^{2}+b^{2}\dots \dots(ii) \end{array}$ From equation(i), $\mathrm{y}=\frac{b x}{a}$...
Solve for x and y :
$px+q y=p-q$
$qx-p y=p+q$
Solution: The given equations are $\begin{array}{l} \mathrm{px}+\mathrm{qy}=\mathrm{p}-\mathrm{q}\dots \dots(i) \\ \mathrm{qx}-\mathrm{py}=\mathrm{p}+\mathrm{q}\dots \dots(ii) \end{array}$...
Solve for x and y :
$\frac{x}{a}+\frac{y}{b}=2$,
$a x-b y=\left(a^{2}-b^{2}\right)$
Solution: The given equations are: $\begin{array}{l} \frac{x}{a}+\frac{y}{b}=2 \\ \Rightarrow \frac{b x+a y}{a b}=2 \quad[\text { Taking LCM }] \\ \Rightarrow \mathrm{bx}+\mathrm{ay}=2 \mathrm{ab}...
Solve for x and y :
$x+y=a+b$,
$a x-b y=a^{2}-b^{2}$
Solution: The given equations are $\begin{array}{l} \mathrm{x}+\mathrm{y}=\mathrm{a}+\mathrm{b}\dots \dots(i) \\ \mathrm{ax}-\mathrm{by}=\mathrm{a}^{2}-\mathrm{b}^{2}\dots \dots(ii) \end{array}$...
Solve for x and y :
$\frac{3}{x}+\frac{6}{y}=7$,
$\frac{9}{x}+\frac{3}{y}=11$
Solution: The given equations can be written as $\begin{array}{l} \frac{3}{x}+\frac{6}{y}=7\dots \dots(i) \\ \frac{9}{x}+\frac{3}{y}=11\dots \dots(ii) \end{array}$ Multiplying equation(i) by 3 and...
Solve for x and y :
$\frac{2}{3 x+2 y}+\frac{3}{3 x-2 y}=\frac{17}{5}$,
$\frac{5}{3 x+2 y}+\frac{1}{3 x-2 y}=2$
Solution: The given equations are $\begin{array}{l} \frac{2}{3 x+2 y}+\frac{3}{3 x-2 y}=\frac{17}{5}\dots \dots(i) \\ \frac{5}{3 x+2 y}+\frac{1}{3 x-2 y}=2\dots \dots(ii) \end{array}$ Substituting...
Solve for x and y :
$\frac{1}{2(x+2 y)}+\frac{5}{3(3 x-2 y)}=-\frac{3}{2}$,
$\frac{1}{4(x+2 y)}-\frac{3}{5(3 x-2 y)}=\frac{61}{60}$ where $\mathrm{x}+2 \mathrm{y} \neq 0$ and $3 \mathrm{x}-2 \mathrm{y} \neq 0$
Solution: The given equations are $\begin{array}{l} \frac{1}{2(x+2 y)}+\frac{5}{3(3 x-2 y)}=-\frac{3}{2}\dots \dots(i) \\ \frac{1}{4(x+2 y)}-\frac{3}{5(3 x-2 y)}=\frac{61}{60}\dots \dots(ii)...
Solve for x and y:
$\frac{1}{3 x+y}+\frac{1}{3 x-y}=\frac{3}{4}$,
$\frac{1}{2(3 x+y)}-\frac{1}{2(3 x-y)}=-\frac{1}{8}$
Solution: The given equations are $\begin{array}{l} \frac{1}{3 x+y}+\frac{1}{3 x-y}=\frac{3}{4}\dots \dots(i) \\ \frac{1}{2(3 x+y)}-\frac{1}{2(3 x-y)}=-\frac{1}{8} \end{array}$ $\frac{1}{3...
Solve for x and y :
$\frac{5}{x}+\frac{2}{y}=6$,
$\frac{-5}{x}+\frac{4}{y}=-3$
Solution: The given equations can be written as $\begin{array}{l} \frac{5}{x}+\frac{2}{y}=6\dots \dots (i) \\ \frac{-5}{x}+\frac{4}{y}=-3\dots \dots(ii) \end{array}$ Adding equation(i) and...
Solve for x and y : $23 x-29 y=98$, $29 x-23 y=110$
Solution: The given equations are: $23 x-29 y=98 \quad \ldots .$ (i) $29 x-23 y=110 \ldots \ldots$ (ii) Adding equation(i) and equation(ii), we obtain: $\begin{array}{l} 52 x-52 y=208 \\ \Rightarrow...
Solve for x and y:
217 x+131 y=913,
131 x+217 y=827
Solution: The given equations are: $\begin{aligned} 217 \mathrm{x}+131 \mathrm{y} =913\dots \dots(i) \\ 131 \mathrm{x}+217 \mathrm{y} =827 \ldots \text {....(ii) } \end{aligned}$ On adding...
Solve for x and y :
$71 x+37 y=253$,
$37 x+71 y=287$
Solution: The given eq. are: $\begin{array}{l} 71 x+37 y=253\dots \dots(i) \\ 37 x+71 y=287 \ldots \ldots \text {...(ii) } \end{array}$ On adding equation(i) and equation(ii), we obtain:...
Solve for x and y :
$\frac{10}{x+y}+\frac{2}{x-y}=4$,
$\frac{15}{x+y}-\frac{9}{x-y}=-2$, where $x \neq y, x \neq-y$
Solution: The given equations are $\frac{10}{x+y}+\frac{2}{x-y}=4 \quad \ldots \ldots$ (i) $\frac{15}{x+y}-\frac{9}{x-y}=-2\dots \dots(ii)$ Substituting $\frac{1}{x+y}=\mathrm{u}$ and...
Solve for x and y :
$\frac{44}{x+y}+\frac{30}{x-y}=10$,
$\frac{55}{x+y}-\frac{40}{x-y}=13$
Solution: The given eq. are $\frac{44}{x+y}+\frac{30}{x-y}=10 \dots \dots(i)$ $\frac{55}{x+y}-\frac{40}{x-y}=13\dots \dots (ii)$ Putting $\frac{1}{x+y}=u$ and $\frac{1}{x-y}=v$, we get: $44 u+30...
Solve for x and y : $\frac{5}{x+1}+\frac{2}{y-1}=\frac{1}{2}$, $\frac{10}{x+1}-\frac{2}{y-1}=\frac{5}{2}$, where $\mathrm{x} \neq 1, \mathrm{y} \neq 1$
Solution: The given eq. are $\frac{5}{x+1}+\frac{2}{y-1}=\frac{1}{2} \quad \ldots \ldots$ (i) $\frac{10}{x+1}-\frac{2}{y-1}=\frac{5}{2}\dots \dots (ii)$ On substituting $\frac{1}{x+1}=\mathrm{u}$...
Solve for x and y :
$\frac{3}{x+y}+\frac{2}{x-y}=2$,
$\frac{3}{x+y}+\frac{2}{x-y}=2$
Solution: The given eq. are $\begin{array}{l} \frac{3}{x+y}+\frac{2}{x-y}=2 \ldots \ldots \text { (i) } \\ \frac{9}{x+y}-\frac{4}{x-y}=1 \ldots \ldots \text { (ii) } \end{array}$ Substituting...
Solve for x and y :
$\frac{5}{x+y}-\frac{2}{x-y}=-1$,
$\frac{15}{x+y}-\frac{7}{x-y}=10$
Solution: The given eq. are $\frac{5}{x+y}-\frac{2}{x-y}=-1 \quad \ldots \ldots \text { (i) }$ $\frac{15}{x+y}-\frac{7}{x-y}=10\dots \dots(ii)$ Substituting $\frac{1}{x+y}=\mathrm{u}$ and...
Solve for x and y:
x + y = 5xy,
3x + 2y = 13xy
Solution: The given eq. are: $x + y = 5xy \dots \dots(i)$ $3x + 2y = 13xy \dots \dots(ii)$ From equation (i), we have: $\begin{array}{l} \frac{x+y}{x y}=5 \\ \Rightarrow \frac{1}{y}+\frac{1}{x}=5...
Solve for x and y :
$4 x+6 y=3 x y$,
$8 x+9 y=5 x y$
Solution: The given eq. are: $\begin{array}{l} 4 x+6 y=3 x y \quad \ldots \ldots(i) \\ 8 x+9 y=5 x y \quad \ldots \ldots(i i) \end{array}$ From eq. (i), we have: $\begin{array}{l} \frac{4 x+6 y}{x...
Solve for x and y :
$\frac{3}{x}+\frac{2}{y}=12$,
$\frac{2}{x}+\frac{3}{y}=13$
Solution: The given eq. are: $\begin{array}{l} \frac{3}{x}+\frac{2}{y}=12 \ldots \ldots \ldots \text { (i) } \\ \frac{2}{x}+\frac{3}{y}=13 \ldots \ldots . \text { (ii) } \end{array}$ Multiplying...
Solve for x and y :
$\frac{5}{x}-\frac{3}{y}=1$,
$\frac{3}{2 x}+\frac{2}{3 y}=5$
Solution: The given eq. are: $\begin{array}{l} \frac{5}{x}-\frac{3}{y}=1 \ldots \ldots(i) \\ \frac{3}{2 x}+\frac{2}{3 y}=5 \ldots \ldots (ii) \end{array}$ Putting $\frac{1}{x}=u$ and...
Solve for x and y:
$\frac{9}{x}-\frac{4}{y}=8$,
$\frac{13}{x}+\frac{7}{y}=101$
Solution: The given eq. are: $\begin{array}{l} \frac{9}{x}-\frac{4}{y}=8 \ldots \ldots . .(i) \\ \frac{13}{x}+\frac{7}{y}=101 \ldots \ldots (ii) \end{array}$ Putting $\frac{1}{x}=u$ and...
Solve for x and y :
$\frac{3}{x}-\frac{1}{y}+9=0$,
$\frac{2}{x}+\frac{3}{y}=5$
Solution: The given eq. are: $\begin{array}{l} \frac{3}{x}-\frac{1}{y}+9=0 \\ \Rightarrow \frac{3}{x}-\frac{1}{y}=-9 \quad \ldots \ldots(i) \\ \Rightarrow \frac{2}{x}-\frac{3}{y}=5 \ldots \ldots...
Solve for x and y:
$2 \mathrm{x}-\frac{3}{y}=9$,
$3 \mathrm{x}+\frac{7}{y}=2$
Solution: The given eq. are: $\begin{array}{l} 2 x-\frac{3}{y}=9 \ldots \ldots \text { (i) } \\ 3 x+\frac{7}{y}=2 \ldots \ldots \text { (ii) } \end{array}$ Putting $\frac{1}{y}=\mathrm{v}$, we...
Solve for x and y :
$x+\frac{6}{y}=6$,
$3 x-\frac{8}{y}=5$
Solution: The given eq. are: $\begin{array}{l} x+\frac{6}{y}=6 \quad \ldots \ldots \text {(i) } \\ 3 x-\frac{8}{y}=5 \ldots \ldots \text { (ii) } \end{array}$ Putting $\frac{1}{y}=\mathrm{v}$, we...
Solve for x and y : $\frac{5}{x}+6 y=13, \frac{3}{x}+4 y=7$
Solution: The given eq. are: $\begin{array}{l} \frac{5}{x}+6 y=13 \ldots \ldots \text { (i) } \\ \frac{3}{x}+4 y=7 \ldots \ldots \text { (ii) } \end{array}$ Putting $\frac{1}{x}=\mathrm{u}$, we...
Solve for x and y : $\frac{x+y-8}{2}=\frac{x+2 y-14}{3}=\frac{3 x+y-12}{11}$
Solution: The given eq. are: $\frac{x+y-8}{2}=\frac{x+2 y-14}{3}=\frac{3 x+y-12}{11}$ i.e., $\frac{x+y-8}{2}=\frac{3 x+y-12}{11}$ On cross multiplication, we obtain: $\begin{array}{l} 11 x+11 y-88=6...
Solve for x and y:
6x + 5y = 7x + 3y + 1 = 2(x + 6y – 1)
Solution: The given equations are: $\begin{array}{l} 6 x+5 y=7 x+3 y+1=2(x+6 y-1) \\ \Rightarrow 6 x+5 y=2(x+6 y-1) \\ \Rightarrow 6 x+5 y=2 x+12 y-2 \\ \Rightarrow 6 x-2 x+5 y-12 y=-2 \\...
Solve for x and y:
7(y + 3) – 2(x + 2) = 14,
4(y – 2) + 3(x – 3) = 2
Solution: The given eq. are: $7(y + 3) – 2(x + 2) = 14$ $\Rightarrow 7y + 21 – 2x – 4 = 14$ $\Rightarrow -2x + 7y = -3 \dots \dots(i)$ and $4(y – 2) + 3(x – 3) = 2$ $\Rightarrow 4y – 8 + 3x – 9 = 2$...
Solve for x and y:
0.3x + 0.5y = 0.5,
0.5x + 0.7y = 0.74
Solution: The given system of eq. is $0.3 \mathrm{x}+0.5 \mathrm{y}=0.5\dots \dots(i)$ $0.5 \mathrm{x}+0.7 \mathrm{y}=0.74 \dots \dots(ii)$ On multiplying equation(i) by 5 and equation(ii) by 3 and...
Solve for x and y:
0.4x + 0.3y = 1.7,
0.7x – 0.2y = 0.8.
Solution: The given system of eq. is $0.4x + 0.3y = 1.7 \dots \dots(i)$ $0.7x – 0.2y = 0.8 \dots \dots(ii)$ On multiplying equation(i) by $0.2$ and equation(ii) by $0.3$ and adding them, we obtain...
Solve for x and y :
$2 x+3 y+1=0$
$\frac{7-4 x}{3}=y$
Solution: The given eq. are: $\begin{array}{l} \frac{7-4 x}{3}=y \\ \Rightarrow 4 x+3 y=7 \dots \dots(i) \end{array}$ $\begin{array}{l} \text { and } 2 x+3 y+1=0 \\ \Rightarrow 2 x+3 y=-1 \ldots...
Solve for x and y :
$2 x+5 y=\frac{8}{3}$,
$3 x-2 y=\frac{5}{6}$
Solution: The given eq. are; $\begin{array}{l} 2 x-5 y=\frac{8}{3} \ldots \ldots(i) \\ 3 x-2 y=\frac{5}{6} \ldots \cdots . . \text { (ii) } \end{array}$ On multiplying equation(i) by 2 and...
Solve for x and y :
$2 x-\frac{3 y}{4}=3$,
$5 x=2 y+7$
Solution: The given eq. are: $\begin{array}{l} 2 \mathrm{x}-\frac{3 y}{4}=3 \ldots \ldots(\mathrm{i}) \\ 5 \mathrm{x}=2 \mathrm{y}+7 \ldots \ldots \text { (ii) } \end{array}$ When multiplying...
Solve for x and y :
$4 x-3 y=8,$
$6 x-y=\frac{29}{3}$
Solution: The given system of eq. is: $\begin{array}{ll} 4 \mathrm{x}-3 \mathrm{y}=8 & \ldots \ldots \text { (i) } \\ 6 \mathrm{x}-\mathrm{y}=\frac{29}{3} & \ldots \ldots \text { (ii) }...
Solve for $\mathrm{x}$ and $\mathrm{y}$ : $\frac{x}{3}+\frac{y}{4}=11, \frac{5 x}{6}-\frac{y}{3}+7=0$
Solution: The given eq. are: $\begin{array}{l} \frac{x}{3}+\frac{y}{4}=11 \\ \Rightarrow 4 x+3 y=132 \ldots \ldots(i) \end{array}$ and $\frac{5 x}{6}-\frac{y}{3}+7=0$ $\Rightarrow 5 x-2 y=-42 \ldots...
Solve for x and y:
9x – 2y = 108,
3x + 7y = 105
Solution: The given system of eq. can be written as: $\begin{array}{cc} 9 \mathrm{x}-2 \mathrm{y}=108 & \ldots \ldots \text { (i) } \\ 3 \mathrm{x}+7 \mathrm{y}=105 & \ldots \text {..(ii) }...
Solve for x and y:
2x – y + 3 = 0,
3x – 7y + 10 = 0
Solution: The given system of eq. is: $\begin{array}{l} 2 x-y+3=0 \ldots \ldots(i) \\ 3 x-7 y+10=0 \ldots \ldots(i i) \end{array}$ From equation(i), write y in terms of $x$ to obtain $y=2 x+3$ On...
Solve for x and y:
3x – 5y – 19 = 0,
-7x + 3y + 1 = 0
Solution: The given system of equation is: $\begin{array}{c} 3 \mathrm{x}-5 \mathrm{y}-19=0 \\ -7 \mathrm{x}+3 \mathrm{y}+1=0 \end{array}$ When multiplying equation(i) by 3 and equation(ii) by 5 ,...
Solve for x and y:
2x – 3y = 13,
7x – 2y = 20
Solution: The given system of eq. is: $\begin{array}{cc} 2 \mathrm{x}-3 \mathrm{y}=13 & \ldots \ldots \text { (i) } \\ 7 \mathrm{x}-2 \mathrm{y}=20 & \ldots \ldots \text { (ii) }...
Solve for x and y:
2x + 3y = 0,
3x + 4y = 5
Solution: The given system of equation is: $\begin{array}{l} 2 x+3 y=0 & \ldots \ldots \text { (i) } \\ 3 x+4 y=5 & \ldots \text {..(ii) } \end{array}$ When multiplying equation(i) by 4 and...
Solve for x and y:
x-y=3
$\frac{x}{3}+\frac{y}{2}=6$
Solution: The given system of equations is $x-y=3 \dots \dots(i)$ $\frac{x}{3}+\frac{y}{2}=6 \dots \dots(ii)$ From equation(i), write y in terms of $x$ to obtain $y=x-3$ When substituting...
Solve for x and y:
x + y = 3,
4x – 3y = 26
Solution: The given system of equation is: $\mathrm{x}+\mathrm{y}=3 \ldots \ldots \text { (i) }$ $4 x-3 y=26 \ldots \ldots \text { (ii) }$ When multiplying equation(i) by 3 , we obtain: $3 x+3 y=9...