Letters are used in algebra in place of an unknown number, giving us algebraic terms like 2x. When algebraic terms are combined with mathematical operations, eg + or - we get an algebraic expression.
When multiplying expressions in brackets, make sure that everything inside the bracket is multiplied by the term (or number) outside the bracket.
Expand \(2(3x + 4)\)
What happens when we have more than a single term or number outside the bracket? What happens when we have another bracket?
For example, if we want to expand \((a + b)(c + d)\), we need to make sure that everything in the first bracket is multiplied by everything in the second bracket.
We can do this in two ways, using boxes or lines.
Expand \((x - 3)(x + 2)\)
Here are both methods, using boxes and lines: