Solve y - 4 = 9

Step by step

The question

Question: solve y − 4 = 9.

1 Remove the − 4

We want y by itself.

The − 4 is in the way.

To remove − 4, we add 4.

We do it on both sides.

Why both sides?

The = sign means both sides are the same amount.

If we change only one side, they are not the same any more.

− 4 and + 4 make zero.

Cross them out.

9 + 4 = 13.

So y = 13!

2 Check

Let's check: put 13 in place of y.

We get 9, the same as the right side.

So y = 13 is right!

Let's look back.

First: remove the − 4.

Last: check.