1. ## Equations Problem

$xy=8$
$x^2+y^2=10$
$(x+y)^2= ?$

2. Originally Posted by sk8teroy
$xy=8$
$x^2+y^2=10$
$(x+y)^2= ?$

Expand: $(x + y)^2 = x^2 + 2xy + y^2 = 2xy + x^2 + y^2$.

Now substitute $xy=8 \,$ and $\, x^2+y^2=10$ .....