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Rational equations

Algebra 2 ยท 20 problems, easy to harder

โ–ถ Watch the first one solved

How we do it

  1. Remove the fractions
  2. Open the brackets
  3. Group like terms
  4. Remove the + 2
  5. Remove the 2
  6. Check

The steps for Solve x/(x + 2) + 1 = 6/(x + 2). Every solution names its steps, so you always know what comes next.

Worked examples

Solve 4/x + 2 = 6 Easy

The question

Question: solve 4/x + 2 = 6.

4x + 2 = 6

First: a bottom can never be 0.

x at the bottom can't be 0.

So x โ‰  0.

x โ‰  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 ร— 4x + x ร— 2 = x ร— 6

x divided by x is 1.

x times 2 is 2x.

x times 6 is 6x.

Write what is left.

No more fractions!

4 + 2x = 6x

2 Get x on one side

There is x on both sides.

We want x on one side only.

So we remove the 2x from the left side.

To remove 2x, we take away 2x.

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

4 + 2x โˆ’ 2x = 6x โˆ’ 2x

+ 2x and โˆ’ 2x make zero.

Cross them out.

6x โˆ’ 2x = 4x.

6x โˆ’ 2x = 4x

Now we have 4 = 4x.

4 = 4x

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

4x = 4

3 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, so they stay equal.

4x4 = 44

4 divided by 4 is 1.

So just x is left.

4 divided by 4 is 1.

44 = 1

So x = 1!

x = 1

4 Check

Let's check: put 1 in place of x.

First the left side.

Left: 41 + 2 = 4 + 2 = 6

Now the right side.

Right: 6

Both sides are 6.

So x = 1 is right!

Both sides equal 6

Let's look back.

First: remove the fractions.

Then: get x on one side.

Then: remove the 4.

Last: check.

Answer
x = 1

โ–ถ Watch it solved

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

The question

Question: solve 5/x โˆ’ 1/2 = 2 over x.

5x โˆ’ 12 = 2x

First: a bottom can never be 0.

x at the bottom can't be 0.

So x โ‰  0.

x โ‰  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 ร— 5x โˆ’ 2x ร— 12 = 2x ร— 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 โˆ’ 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 โˆ’ x โˆ’ 10 = 4 โˆ’ 10

10 and โˆ’ 10 make zero.

Cross them out.

4 โˆ’ 10 = โˆ’6.

4 โˆ’ 10 = โˆ’6

Now we have โˆ’x = โˆ’6.

โˆ’x = โˆ’6

3 Remove the โˆ’1

โˆ’x means โˆ’1 times x.

We want just x.

To remove times โˆ’1, we divide by โˆ’1.

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

โˆ’xโˆ’1 = โˆ’6โˆ’1

โˆ’1 divided by โˆ’1 is 1.

So just x is left.

โˆ’6 divided by โˆ’1 is 6.

โˆ’6โˆ’1 = 6

So x = 6!

x = 6

4 Check

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

First the left side.

Left: 56 โˆ’ 12 = 56 โˆ’ 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 โˆ’1.

Last: check.

Answer
x = 6

โ–ถ Watch it solved

Solve x/(x + 2) + 1 = 6/(x + 2) Harder

The question

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

xx + 2 + 1 = 6x + 2

First: a bottom can never be 0.

x = โˆ’2 makes x + 2 0.

So x โ‰  โˆ’2.

x โ‰  โˆ’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) ร— xx + 2 + (x + 2) ร— 1 = (x + 2) ร— 6x + 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!

x + (x + 2) = 6

2 Open the brackets

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

x + x + 2 = 6

3 Group like terms

Terms are the parts between the + and โˆ’ signs.

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

All the x terms go together.

x + x = 2x.

x + x = 2x

Now we have 2x + 2 = 6.

2x + 2 = 6

We want x by itself.

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

The + 2 is on the outside, so it comes off first.

Then the times 2.

4 Remove the + 2

To remove + 2, we take away 2.

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

2x + 2 โˆ’ 2 = 6 โˆ’ 2

+ 2 and โˆ’ 2 make zero.

Cross them out.

6 โˆ’ 2 = 4.

6 โˆ’ 2 = 4

Now we have 2x = 4.

2x = 4

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.

2x2 = 42

2 divided by 2 is 1.

So just x is left.

4 divided by 2 is 2.

42 = 2

So x = 2!

x = 2

6 Check

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

First the left side.

Left: 22 + 2 + 1 = 24 + 1 = 12 + 1 = 12 + 22
= 32

Now the right side.

Right: 62 + 2 = 64 = 32

Both sides are 3/2.

So x = 2 is right!

Both sides equal 32

Let's look back.

First: remove the fractions.

Then: open the brackets.

Then: group like terms.

Then: remove the + 2.

Then: remove the 2.

Last: check.

Answer
x = 2

โ–ถ Watch it solved

Practice

Try each one, then open the answer. Stuck? Open the problem to watch every step.

Easy

  1. 4/x + 2 = 6
    Answer
    x = 1
  2. 12/x + 1 = 4
    Answer
    x = 4
  3. 6/x - 1 = 2
    Answer
    x = 2
  4. 15/x = 2 + 5/x
    Answer
    x = 5
  5. 3/x + 3/x = 2
    Answer
    x = 3
  6. 3/x + 2 = 1/x
    Answer
    x = โˆ’1
  7. 2/x + 3 = 1/x + 4
    Answer
    x = 1

Medium

  1. 5/x - 1/2 = 2/x
    Answer
    x = 6
  2. 1/x + 1/(2x) = 3/4
    Answer
    x = 2
  3. 4/(x - 2) + 1 = 3
    Answer
    x = 4
  4. 5/(x + 2) = 1 + 3/(x + 2)
    Answer
    x = 0
  5. 6/(x + 1) = 2 + 3/(x + 1)
    Answer
    x = 12
  6. (x + 4)/x = 3 + 2/x
    Answer
    x = 1
  7. 5/(2x) + 1/x = 7/4
    Answer
    x = 2
  8. 8/x - 3 = 1
    Answer
    x = 2

Harder

  1. x/(x + 2) + 1 = 6/(x + 2)
    Answer
    x = 2
  2. 1/x - 1/(3x) = 2/9
    Answer
    x = 3
  3. 10/(x - 1) - 2 = 6/(x - 1)
    Answer
    x = 3
  4. x/(x - 3) = 3/(x - 3) + 2
    Answer
    x = 3 makes a bottom 0: no solution.
  5. 2x/(x - 1) - 2/(x - 1) = 3
    Answer
    x = 1 makes a bottom 0: no solution.