Brackets are used to control the priority of calculations, just as they do in arithmetic.

An expression such as `4(x + 3)` means that the 4 multiplies both the `x` and the 3. Brackets are a bit like paper bags: there is `x + 3` in each bag, and if there are 4 bags then there are 4 lots of `x` and 4 lots of 3.

Removing the brackets is called **expanding** the expression, or *expanding the brackets*. Each term in the brackets has to be multiplied by the term outside the bracket

`4(x + 3)`

`= 4 xx x + 4 xx 3`

`= 4x+ 12`

Expand `3(2x - 7)`

`3(2x - 7)`

`= 3 xx 2x - 3 xx 7` `= 6x - 21`

Answer: `6x - 21`

Expand `3a(2a + 4) + 6a`

Expand the brackets:

`3a xx 2a + 3a xx 4 + 6a`

`= 6a^2 + 12a + 6a`

`= 6a^2 + 18a`

Answer: `6a^2 + 18a`

See also Using Brackets

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