Question

What do you mean by (A-B)²=

Answer 1

In order to prove (a-b)^2 = a^2-2ab+b^2, let us expand the LHS.

(a-b)^2

= (a-b)(a-b)

= a(a-b) - b(a-b)

= a^2 -ab - ba + b^2

= a^2 -2ab + b^2 (ab = ba)

Therefore,

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

Answer 2

$(a - b) {}^{2} = (a + b) {}^{2} - 4ab \\ = \geqslant \: real \: value \: is \: {a}^{2} + {b}^{2} - 2ab$