Question

if sum of the square's of zeroes of the quadratic polynomial f(x)=x^2_4x+k is 20 then find the value of k

Answer 1

Given sum of zeroes, x = 20

Therefore
f(x) = x^2 -4x + k =0

f(20) = (20)(20) - 4(20) + k =0
= 400 - 80 + k =0
= 320 + k = 0
Hence, k = -320