Question

Se x-y =7a xy =60 entao o valor de x2+y2 e

Answer 1

(x - y)² = x² - 2.x.y + y²

x² + y² = (x - y)² + 2xy
x² + y² = (7)² + 2*60
x² + y²= 49 + 120 = 169