Steply

Solve 10/x − 3 = 2.

Step by step, with the reason for every step · GCSE Maths Higher Paper 1 · GCSE Maths

Step by step

The question

Question: solve 10/x − 3 = 2.

10x − 3 = 2

x is at the bottom of a fraction.

First: a bottom can never be 0.

We can't divide by 0.

x at the bottom can't be 0.

So x ≠ 0.

x ≠ 0

1 Remove the fractions

The bottom is x.

Times x will remove it.

We multiply every part by x.

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

x × 10x − x × 3 = x × 2

Each bottom goes into x.

So in each fraction, we can cross out the bottom.

What is left of x stays.

x divided by x is 1.

x times 3 is 3x.

x times 2 is 2x.

This is what is left of x in each part.

x ÷ x = 1

We write the equation again.

No more fractions!

10 − 3x = 2x

2 Get x on one side

There is x on both sides.

We want x on one side only.

The numbers in front of x are −3 and 2.

We remove the smaller one, −3x, so the x part that is left is plus.

So we remove the −3x from the left side.

To remove −3x, we add 3x.

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

10 − 3x + 3x = 2x + 3x

− 3x and + 3x cancel each other.

They make zero.

2x + 3x = 5x.

2x + 3x = 5x

Now we have 10 = 5x.

10 = 5x

Let's swap the two sides, so x is on the left.

Both sides are the same amount, so we can swap them.

5x = 10

So after step 2: we added 3x, and now we have 5x = 10.

← step 2: added 3x

Is x alone now?

Not yet: 5x means 5 times x.

How do we remove it?

3 Remove the 5

To remove times 5, we divide by 5.

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

5x5 = 105

5 divided by 5 is 1.

They cancel each other.

So just x is left.

10 divided by 5 is 2.

105 = 2

So x = 2!

x = 2

4 Check

Let's check: put 2 in place of x.

First the left side.

Left: 102 − 3 = 5 − 3 = 2

Now the right side.

Right: 2

Both sides are 2.

So x = 2 is right!

Both sides equal 2

Let's look back.

First: remove the fractions.

Then: get x on one side.

Then: remove the 5.

Last: check.

Answer
x = 2

Your turn

Try this one yourself, then check your answer:

Solve 7x − 3 = 4
Show the answer
x = 1

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