Question

If p,q are the zeros of the polynomial f(x)=x²-2x-8 then find the value of p²+q²

Answer 1

p+q= -b/a = -(-2)= 2
pq= c/a= -8
(p+q)²=( 2)²
p2+q2+2pq= 4
p2+q2+2(-8)= 4
p2+q2= 20

Answer 2

So the zeros are p and q
On factorization of equation we get 4 and - 2 as zeros
So, p^2+q^2
(4)^2 + (-2)^2
16 + 4
20