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Solve 5/(x + 2) = 1 + 3/(x + 2)

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

Step by step

The question

Question: solve 5/(x + 2) = 1 + 3/(x + 2).

5x + 2 = 1 + 3x + 2

First: a bottom can never be 0.

x = −2 makes x + 2 0.

So x ≠ −2.

x ≠ −2

1 Remove the fractions

The bottom is (x + 2).

Times (x + 2) will remove it.

We multiply every part by (x + 2).

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

(x + 2) × 5x + 2 = (x + 2) × 1 + (x + 2) × 3x + 2

(x + 2) divided by (x + 2) is 1.

(x + 2) times 1 is (x + 2).

(x + 2) divided by (x + 2) is 1.

Write what is left.

No more fractions!

5 = (x + 2) + 3

2 Open the brackets

A bracket with a plus or nothing in front can just be removed.

5 = x + 2 + 3

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.

2 + 3 = 5.

2 + 3 = 5

Now we have 5 = x + 5.

5 = x + 5

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

x + 5 = 5

4 Remove the + 5

We want x by itself.

The + 5 is in the way.

To remove + 5, we take away 5.

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

x + 5 − 5 = 5 − 5

+ 5 and − 5 make zero.

Cross them out.

5 − 5 = 0.

5 − 5 = 0

So x = 0!

x = 0

5 Check

Let's check: put 0 in place of x.

First the left side.

Left: 50 + 2 = 52

Now the right side.

Right: 1 + 30 + 2 = 1 + 32 = 22 + 32 = 52

Both sides are 5/2.

So x = 0 is right!

Both sides equal 52

Let's look back.

First: remove the fractions.

Then: open the brackets.

Then: group like terms.

Then: remove the + 5.

Last: check.

Answer
x = 0

Your turn

Try this one yourself, then check:

9x + 2 = 1 + 1x + 2
Show the answer
x = 6

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