Question

If 1 and -1 are zeros of polynomial p x is equal to a x cube + x square - 2 x + b find a and b

Answer 1

Answer:

a = 2 and b=1

Step-by-step explanation:

1 and - 1 are zeroes of polynomial

$p(x) = a {x}^{3} + {x}^{2} - 2x + b \\ inserting \: x \: as \: 1 \: and \: - 1$

x=1 then p(x) = a+1-2+b = a+b-1

x=-1 then p(x) = - a+1+2+b = b-a+3

Solving 2 equations

a+b=1 and b-a=-3

We get

b=-1 and a=2