Question

Sendo (a+b)² = 20, e ab=6, determine o valor de a²+b².

Answer 1

Olá,

$(a+b)^{2} = 20\\a^{2}+ 2.a.b + b^{2} =20 \\a^{2}+2.6+ b^{2} =20\\a^{2}+12+ b^{2} =20\\a^{2}+ b^{2}=20-12 \\a^{2}+ b^{2}=8$

Answer 2

(a + b) ² =

a² + 2.a.b + b² = 20

substituindo

a² + b² +2.6 = 20

a² + b² + 12 =20

a² + b² = 20 - 12

a² + b² = 8