Kahlil said that using the equation (a + b)2 = a2 + 2ab + b2, he can find a similar equation for (a - b)2. Examine his argument.

Question

(a - b)2 = [a + (-b)]2
= a2 + 2a(-b) + (-b)2
= a2 – 2ab + b2

Answer 1

He is correct.