Solve x + 7 = 12 Easy

The question

Question: solve x + 7 = 12.

1 Remove the + 7

We want x by itself.

The + 7 is in the way.

To remove + 7, we take away 7.

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.

+ 7 and − 7 make zero.

Cross them out.

12 − 7 = 5.

So x = 5!

2 Check

Let's check: put 5 in place of x.

We get 12, the same as the right side.

So x = 5 is right!

Let's look back.

First: remove the + 7.

Last: check.

▶ Watch it solved

Solve 5 - 2x = 11 Medium

The question

Question: solve 5 − 2x = 11.

We want x by itself.

Two things are stuck to x: times −2 and + 5.

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

Then the times −2.

1 Remove the 5

To remove 5, we take away 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.

11 − 5 = 6.

Now we have −2x = 6.

2 Remove the −2

−2x means −2 times x.

We want just x.

To remove times −2, we divide by −2.

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

−2 divided by −2 is 1.

So just x is left.

6 divided by −2 is −3.

So x = −3!

3 Check

Let's check: put −3 in place of x.

We get 11, the same as the right side.

So x = −3 is right!

Let's look back.

First: remove the 5.

Then: remove the −2.

Last: check.

▶ Watch it solved

Solve 6n - 4 = 2n - 4 Harder

The question

Question: solve 6n − 4 = 2n − 4.

1 Get n on one side

There is n on both sides.

We want n on one side only.

So we remove the 2n from the right side.

To remove 2n, we take away 2n.

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.

2n and − 2n make zero.

Cross them out.

6n − 2n = 4n.

Now we have 4n − 4 = −4.

We want n by itself.

Two things are stuck to n: times 4 and − 4.

The − 4 is on the outside, so it comes off first.

Then the times 4.

2 Remove the − 4

To remove − 4, we add 4.

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

− 4 and + 4 make zero.

Cross them out.

−4 + 4 = 0.

Now we have 4n = 0.

3 Remove the 4

4n means 4 times n.

We want just n.

To remove times 4, we divide by 4.

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

4 divided by 4 is 1.

So just n is left.

0 divided by 4 is 0.

So n = 0!

4 Check

Let's check: put 0 in place of n.

First the left side.

Now the right side.

Both sides are −4.

So n = 0 is right!

Let's look back.

First: get n on one side.

Then: remove the − 4.

Then: remove the 4.

Last: check.

▶ Watch it solved