Question

xy=10 e x-y= 40 resolva x^2+y^2

Answer 1

(2x , y) = (3y-9 , 8-x)
$\left \{ {{2x=3y-9} \atop {y=8-x}} \right.$
2x= 3(8-x) - 9
2x= 24 - 3x - 9
2x + 3x = 24 - 9
5x= 15
x= 3

y= 8 - x
y= 8 - 3
y= 5

x^2 + y^2 = 3^2 + 5^2 = 9 + 25= 34