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Solve 5/x - 1/2 = 2/x

Step by step, with the reason for every step · Rational equations · Algebra 2

Step by step

The question

Question: solve 5/x − 1/2 = 2 over x.

5x − 12 = 2x

First: a bottom can never be 0.

x at the bottom can't be 0.

So x ≠ 0.

x ≠ 0

1 Remove the fractions

The bottoms are x and 2.

2x can be divided by all of them.

We multiply every part by 2x.

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

2x × 5x − 2x × 12 = 2x × 2x

2x divided by x is 2.

2x divided by 2 is x.

2x divided by x is 2.

Write what is left.

No more fractions!

10 − x = 4

2 Remove the 10

We want x by itself.

The 10 is in the way.

To remove 10, we take away 10.

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

10 − x − 10 = 4 − 10

10 and − 10 make zero.

Cross them out.

4 − 10 = −6.

4 − 10 = −6

Now we have −x = −6.

−x = −6

3 Remove the −1

−x means −1 times x.

We want just x.

To remove times −1, we divide by −1.

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

−x−1 = −6−1

−1 divided by −1 is 1.

So just x is left.

−6 divided by −1 is 6.

−6−1 = 6

So x = 6!

x = 6

4 Check

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

First the left side.

Left: 56 − 12 = 56 − 36 = 13

Now the right side.

Right: 26 = 13

Both sides are 1/3.

So x = 6 is right!

Both sides equal 13

Let's look back.

First: remove the fractions.

Then: remove the 10.

Then: remove the −1.

Last: check.

Answer
x = 6

Your turn

Try this one yourself, then check:

7x − 32 = 1x
Show the answer
x = 4

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