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Solve 10/(x - 1) - 2 = 6/(x - 1)

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

Step by step

The question

Question: solve 10/(x − 1) − 2 = 6/(x − 1).

10x − 1 − 2 = 6x − 1

First: a bottom can never be 0.

x = 1 makes x − 1 0.

So x ≠ 1.

x ≠ 1

1 Remove the fractions

The bottom is (x − 1).

Times (x − 1) will remove it.

We multiply every part by (x − 1).

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

(x − 1) × 10x − 1 − (x − 1) × 2 = (x − 1) × 6x − 1

(x − 1) divided by (x − 1) is 1.

(x − 1) times 2 is 2(x − 1).

(x − 1) divided by (x − 1) is 1.

Write what is left.

No more fractions!

10 − 2(x − 1) = 6

2 Open the brackets

The −2 in front of the bracket multiplies every part inside.

So we write −2 times each part.

10 − 2 × x − 2 × (−1) = 6

Work out each multiplication.

10 − 2x + 2 = 6

3 Group like terms

Terms are the parts between the + and − signs.

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

Plain numbers go together.

10 + 2 = 12.

10 + 2 = 12

Now we have 12 − 2x = 6.

12 − 2x = 6

We want x by itself.

Two things are stuck to x: times −2 and + 12.

The + 12 is on the outside, so it comes off first.

Then the times −2.

4 Remove the 12

To remove 12, we take away 12.

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

12 − 2x − 12 = 6 − 12

12 and − 12 make zero.

Cross them out.

6 − 12 = −6.

6 − 12 = −6

Now we have −2x = −6.

−2x = −6

5 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.

−2x−2 = −6−2

−2 divided by −2 is 1.

So just x is left.

−6 divided by −2 is 3.

−6−2 = 3

So x = 3!

x = 3

6 Check

Let's check: put 3 in place of x.

First the left side.

Left: 103 − 1 − 2 = 102 − 2 = 5 − 2 = 3

Now the right side.

Right: 63 − 1 = 62 = 3

Both sides are 3.

So x = 3 is right!

Both sides equal 3

Let's look back.

First: remove the fractions.

Then: open the brackets.

Then: group like terms.

Then: remove the 12.

Then: remove the −2.

Last: check.

Answer
x = 3

Your turn

Try this one yourself, then check:

5x − 1 − 3 = 2x − 1
Show the answer
x = 2

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