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Solve x/2 + x/3 = 10

Step by step, with the reason for every step · Linear equations · Algebra 1

Step by step

The question

Question: solve x/2 + x/3 = 10.

x2 + x3 = 10

1 Remove the fractions

The bottom numbers are 2 and 3.

6 can be divided by all of them.

We multiply every part by 6.

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.

6 × x2 + 6 × x3 = 6 × 10

6 divided by 2 is 3.

6 divided by 3 is 2.

Write what is left.

3 × x + 2 × x = 6 × 10

Do the multiplications.

No more fractions!

3x + 2x = 60

2 Group like terms

Terms are the parts between the + and − signs.

Like terms are the same kind: same letters, same powers.

All the x terms go together.

3x + 2x = 5x.

3x + 2x = 5x

Now we have 5x = 60.

5x = 60

3 Remove the 5

5x means 5 times x.

We want just x.

To remove times 5, we divide by 5.

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

5x5 = 605

5 divided by 5 is 1.

So just x is left.

60 divided by 5 is 12.

605 = 12

So x = 12!

x = 12

4 Check

Let's check: put 12 in place of x.

Check: 122 + 123 = 6 + 4 = 10

We get 10, the same as the right side.

So x = 12 is right!

Let's look back.

First: remove the fractions.

Then: group like terms.

Then: remove the 5.

Last: check.

Answer
x = 12

Your turn

Try this one yourself, then check:

x2 + x8 = 10
Show the answer
x = 16

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