Question

5
If x + y = 8 and x - y = 2, find the value of 2x^2 + 2y^2.
Hint. 2(x^2 + y^2) = (x + y)^2 + (x - y)^2.​

Answer 1

Answer:

First you solve ,

(x+y)^2+(x-y)^2

=8^2+2^2

=64+4

=68

therefore,

=2x^2+2y^2

=(x+y)^2+(x-y)^2

=68