Question

Vamos calcular : (a - b ) (2a - 5b)

Answer 1

(a-b)²=a²-2.a.b+b²=a²-2ab+b²
(2a-5b)²=2a²+2.2a.5b+5b²=4a²+20ab+25b²

Answer 2

a resposta seria -3.
espero ter ajudado