Question

a² + b² = 40 e ab = 10, calcule (a + b)². 

Answer 1

$(a+b)^2 = a^2 +2ab+b^2$

$(a+b)^2 = (a^2+b^2) +2ab$

$(a+b)^2 = 40+20$

$(a+b)^2 =60$