Question

Sendo x²+y²=20 e xy= -4 determine o valor de (x+y)²

Answer 1

(x + y)²

= (x)² + 2(x)(y) + y²

= x² + 2xy + y²

= 2xy + x² + y²

= 2*(-4) + 20

= - 8 + 20

= 12