Solve 3y - 5 = 16

Step by step

The question

Question: solve 3y − 5 = 16.

We want y by itself.

Two things are stuck to y: times 3 and − 5.

The − 5 is on the outside, so it comes off first.

Then the times 3.

1 Remove the − 5

To remove − 5, we add 5.

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.

− 5 and + 5 make zero.

Cross them out.

16 + 5 = 21.

Now we have 3y = 21.

2 Remove the 3

3y means 3 times y.

We want just y.

To remove times 3, we divide by 3.

We do it on both sides, so they stay equal.

3 divided by 3 is 1.

So just y is left.

21 divided by 3 is 7.

So y = 7!

3 Check

Let's check: put 7 in place of y.

We get 16, the same as the right side.

So y = 7 is right!

Let's look back.

First: remove the − 5.

Then: remove the 3.

Last: check.