Question

Given that x-y=7 and xy=8, find the value of (x+y) (x+y)

Answer 1

Answer:

Given:

xy =8

x-y=7

x=7+y

Now, (x+y) (x+y)

=(x+y)²

=x²+2xy +y²

=(7+y)² +2×8+y²

=49+14y+y²+16+y²

=2y²+14y+65

Therefore, (x+y) (x+y) =2y²+14y+65