Question

if alpha and beta are the zeros of x^2-5x+4 find 1/α+1/β-2αβ

Answer 1

see the Sol in the above page..
hope that it will clear your doubts..☺

Answer 2

Sum of roots z+a =5
Product of roots = za = 4
1/z+1/a-2za
(Z+a)/za -2za
5/4-8=-27/4 answer is correct