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Solve x/8 = 3/4

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

Step by step

The question

Question: solve x/8 = 3/4.

Two fractions are equal.

x8 = 34

1 Cross multiply

When two fractions are equal, we can cross multiply.

These two are equal.

x × 4 = 3 × 8

Work out the multiplications.

4x = 24

2 Remove the 4

4x means 4 times x.

We want just x.

To remove times 4, we divide by 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.

4x4 = 244

4 divided by 4 is 1.

So just x is left.

24 divided by 4 is 6.

244 = 6

So x = 6!

x = 6

3 Check

Let's check: put 6 in place of x.

First the left side.

Left: 68 = 6÷28÷2 = 34

Now the right side.

Right: 34

Both sides are 3/4.

So x = 6 is right!

Both sides equal 34

Let's look back.

First: cross multiply.

Then: remove the 4.

Last: check.

Answer
x = 6

Your turn

Try this one yourself, then check:

x6 = 24
Show the answer
x = 3

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