Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients.

Solutions:

Concept: When a polynomial is zeroed, the values of x that meet the equation y = f are considered zeros (x). There is a f(x) function, and the zeros of a polynomial are all of the values of x for which the y value equals zero. The degree of the equation y = f determines the number of zeros in a polynomial and vice versa (x).

Calculation:

  • x2ā€“2x ā€“8

Factorising the polynomial using splitting method:

ā‡’x2ā€“ 4x+2xā€“8 = x(xā€“4)+2(xā€“4) = (x-4)(x+2)

Therefore, zeroes of polynomial equation x2ā€“2xā€“8 are (4, -2)

Sum of zeroes = 4ā€“2 = 2 = -(-2)/1 = -(Coefficient of x)/(Coefficient of x2)

Product of zeroes = 4Ɨ(-2) = -8 =-(8)/1 = (Constant term)/(Coefficient of x2)

  • 4s2ā€“4s+1

Factorising the polynomial using splitting method:

ā‡’4s2ā€“2sā€“2s+1 = 2s(2sā€“1)ā€“1(2s-1) = (2sā€“1)(2sā€“1)

Therefore, zeroes of polynomial equation 4s2ā€“4s+1 are (1/2, 1/2)

Sum of zeroes = (Ā½)+(1/2) = 1 = -4/4 = -(Coefficient of s)/(Coefficient of s2)

Product of zeros = (1/2)Ɨ(1/2) = 1/4 = (Constant term)/(Coefficient of s)

  • 6x2ā€“3ā€“7x

Factorising the polynomial using splitting method:

ā‡’6x2ā€“7xā€“3 = 6xā€“ 9x + 2x ā€“ 3 = 3x(2x ā€“ 3) +1(2x ā€“ 3) = (3x+1)(2x-3)

Therefore, zeroes of polynomial equation 6x2ā€“3ā€“7x are (-1/3, 3/2)

Sum of zeroes = -(1/3)+(3/2) = (7/6) = -(Coefficient of x)/(Coefficient of x2)

Product of zeroes = -(1/3)Ɨ(3/2) = -(3/6) = (Constant term) /(Coefficient of x)

  • 4u2+8u

Factorising the polynomial using splitting method:

ā‡’ 4u(u+2)

Therefore, zeroes of polynomial equation 4u2 + 8u are (0, -2).

Sum of zeroes = 0+(-2) = -2 = -(8/4) = = -(Coefficient of u)/(Coefficient of u2)

Product of zeroes = 0Ɨ-2 = 0 = 0/4 = (Constant term)/(Coefficient of u)

  • t2ā€“15

Factorising the polynomial using splitting method:

ā‡’ t2 = 15 or t = Ā±āˆš15

Therefore, zeroes of polynomial equation t2 ā€“15 are (āˆš15, -āˆš15)

Sum of zeroes =āˆš15+(-āˆš15) = 0= -(0/1)= -(Coefficient of t) / (Coefficient of t2)

Product of zeroes = āˆš15Ɨ(-āˆš15) = -15 = -15/1 = (Constant term) / (Coefficient of t)

  • 3x2ā€“xā€“4

Factorising the polynomial using splitting method:

ā‡’ 3x2ā€“4x+3xā€“4 = x(3x-4)+1(3x-4) = (3x ā€“ 4)(x + 1)

Therefore, zeroes of polynomial equation3x2 ā€“ x ā€“ 4 are (4/3, -1)

Sum of zeroes = (4/3)+(-1) = (1/3)= -(-1/3) = -(Coefficient of x) / (Coefficient of x2)

Product of zeroes=(4/3)Ɨ(-1) = (-4/3) = (Constant term) /(Coefficient of x)