Multiplication
Square of a Binomial
Formulas to Remember
(a + b)2 = a2 + 2ab + b2
and
(a – b)2 = a2 – 2ab + b2
*Note: Don’t make the common mistake of saying (a + b)2 = a2 + b2, they are not equal. To see why, try substituting numbers for a and b into the equation (for example, a = 4 and b = 3) and you will see that it is not a true statement. The middle term, 2ab, is needed to make the equation true.