If x + y = 12 and xy = 14, find the value of (x2 + y2).
Given,
x + y = 12
Let’s square the both sides,
We get;
= (x + y)2 = (12)2
= x2 + y2 + 2xy = 144
= x2 + y2 = 144 – 2xy
Also given,
xy = 14
= x2 + y2 = 144 – 2(14)
= x2 + y2 = 144 – 28
= x2 + y2 = 116
So, the value of (x2 + y2) is 116.