A binomial expression is one that has two terms, such as 3a - 1
When we multiply two binomials, we must carefully multiply each term in one bracket with each term in the other bracket.
Simplify the following squared expression:
(a - 1)2
First, we write the calculation using two brackets.
(a - 1) (a - 1)
We "explode" the first bracket and repeat the second bracket like this:
a (a - 1) - 1(a - 1)
Multiply out the brackets
a2 - a - a + 1
Simplify by collecting like terms
a2 - 2a + 1