Step by step
The question
Question: simplify 7y − 2y.
Simplify means: write it shorter, with the same value.
7y − 2y
1 Group like terms
Terms are the parts between the + and − signs.
Like terms are the same kind: same letters, same powers.
All the y terms go together.
Each colour is one kind.
like terms = same letters,
same powers
7y − 2y is 5y.
It is like 7 apples take away 2 apples: that is 5 apples.
7y − 2y = 5y
So the expression is 5y.
= 5y
2 Check
Let's check.
We pick a number for each letter: y = 2.
We put it into the start.
Start: 7 × 2 − 2 × 2 = 14 − 4 = 10
Now into our answer.
Answer: 5 × 2 = 10
Both give 10.
Same value, so 5y is right!
Both give 10
Let's look back.
First: group like terms.
Last: check.
Answer
= 5y