Question

Sendo (a+b)²=83 e ab=−23, calcule o valor de a²+b².

Answer 1

(a+b)2 = a2 + 2ab + b2 

a2 + 2 x (-23) + b2 = 83
a2 + -46  + b2 = 83
a2 + b2 = 83 + 46
a2 + b2 = 129

Answer 2

                 (a + b)² = 83 **********  ab = - 23 ********* a²+b² =

                  a² + 2ab + b² = 83
                  a² + b² + 2ab = 83
                  a² + b² = 83 - 2ab
                  a² + b² = 83 - 2(-23)
                  a² + b² = 83 + 46
                  a² + b² = 129