Question

if sum of the squares if the zeros of the quadratic polynomial f(x)= x^2 -8x+ k is 40 find k

Answer 1

Let a and b be two zeroes
So
a + b =-(- 8) = 8
a*b = k

a2 + b2 = 40
(a + b) ^2 - 2a*b = 40
8*8 - 2k = 40
64 - 2k = 40
2k = 24
K = 12