Question

If sum of the square of the zeros of the poly f(x)=x2-8x+k is 40 then find thw value of k

Answer 1

We use vietas to find that the sum of the roots is 64, so k=(64-40)/2=12, and when we plug this in, we get the roots to be 6 and 2, and the sum of their squares is 40, so k is indeed 12.