Expanding brackets means removing brackets by multiplying everything inside of the bracket by what is just outside of the bracket.
Let's have a look at a few examples.
Expand 3(4x − 2)
We will multiply 3 by 4x and 3 by −2
3 × 4x = 12x
3 × −2 = −6
Now we put these together to get the final answer: 12x − 6
−5(7 − 5b)
We will follow the same method, but we need to be careful with the negative sign.
−5 × 7 = −35
−5 × − 5b = 25b (positive!)
So the answer is −35 + 25b
- when we multiply a negative by a positive number, the answer is negative
- when we multiply two negative numbers, the answer will be positive.