In this activity, we are going expand double brackets and we are going to collect any like terms to simplify.
Recap - Single Brackets
When we multiply single brackets, we multiply all the terms in the bracket by the term outside.
For double brackets we multiply everything in the first bracket by everything in the second bracket.
Let's have a look at a question.
Expand and simplify
(a + 3) (a + 4)
To make sure do do not miss any terms we can draw a grid and multiply in there.
Multiply each term together a x a, a x 3, a x 4, 3 x 4
There are four terms in the answer as you can see, but the 4a and 3a are like terms and can be added together to leave just three terms in the answer.
Therefore, the answer is a2 + 7a + 12
Let's try some questions!