India Site

Solve the following equations using graphical method: $a+b=4$ $2a–3b=3$

Given,

$a+b=4$……. (i)

$2a–3b=3$……. (ii)

From equation (i),

⇒ $b=(4–a)$

When $a=4$, we get $b=(4–4)=0$

When $a=2$, we get $b=(4–2)=2$

Thus, we have the following table giving Points on the line $a+b=4$

a $4$ $2$
b $0$ $2$

From equation (ii),

We solve for b:

⇒ $b=(2a–3)/3$

So, when $a=3$

$b=(2(3)–3)/3=1$

And, when $a=0$

⇒ $b=(2(0)–3)/3=-1$

Thus, we have the following table giving Points on the line $2a–3b=3$

a $3$ $0$
b $1$ $-1$

 

Graph of the equations (i) and (ii) is given below:

In given graph, the two lines intersect at a single Point P $(3,1)$

Thus, $a=3$ and $b=1$.