Step by step
The question
Question: simplify 3(2y − 1).
Simplify means: write it shorter, with the same value.
3(2y − 1)
1 Open the brackets
The 3 in front of the bracket multiplies every part inside.
a(b + c) = ab + ac
So we write 3 times each part.
= 3(2y) + 3(−1)
− × + = −
Watch the signs.
3 times 2y is 6y.
3 times (−1) is −3.
= 6y − 3
2 Check
Let's check.
We pick a number for each letter: y = 2.
We put it into the start.
Start: 3 × (2 × 2 − 1) = 3 × 3 = 9
Now into our answer.
Answer: 6 × 2 − 3 = 12 − 3 = 9
Both give 9.
Same value, so 6y − 3 is right!
Both give 9
Let's look back.
First: open the brackets.
Last: check.
Answer
= 6y − 3