Question

Se x²+y²=20 e xy=3 quato vale (x+y)²

Answer 1

(x+y)^2= x^2 + 2xy + y^2
Sabemos que:
x^2 + y^2 = 20 e x.y= 3
Portanto: (x+y)^2 = 20 + 2.3 = 26