(a + b)2 = a2 + b2 + 2ab
Working forwards - ExpansionFor example, the expression (2x + 3y)2 can be expanded as follows:
= (2x)2 + (3y)2 + 2(2x)(3y)
= 4x2 + 9y2 + 12xy
Working backwards - FactorizationFor example, the expression x2 + 100y2 + 20xy can be factored as follows:
x2 + (10y)2 + 2(x)(10y)On comparing it with a2 + b2 + 2ab
(x + 10y)2.. which is the factored form.