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Solve (x + 4)/x = 3 + 2/x

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

Step by step

The question

Question: solve (x + 4)/x = 3 + 2 over x.

x + 4x = 3 + 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 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 × x + 4x = x × 3 + x × 2x

x divided by x is 1.

x times 3 is 3x.

x divided by x is 1.

Write what is left.

No more fractions!

(x + 4) = 3x + 2

2 Open the brackets

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

x + 4 = 3x + 2

3 Get x on one side

There is x on both sides.

We want x on one side only.

So we remove the x from the left side.

To remove x, we take away x.

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

x + 4 − x = 3x + 2 − x

x and − x make zero.

Cross them out.

3x − x = 2x.

3x − x = 2x

Now we have 4 = 2x + 2.

4 = 2x + 2

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

2x + 2 = 4

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 − 2 = 4 − 2

+ 2 and − 2 make zero.

Cross them out.

4 − 2 = 2.

4 − 2 = 2

Now we have 2x = 2.

2x = 2

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 = 22

2 divided by 2 is 1.

So just x is left.

2 divided by 2 is 1.

22 = 1

So x = 1!

x = 1

6 Check

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

First the left side.

Left: 1 + 41 = 51 = 5

Now the right side.

Right: 3 + 21 = 3 + 2 = 5

Both sides are 5.

So x = 1 is right!

Both sides equal 5

Let's look back.

First: remove the fractions.

Then: open the brackets.

Then: get x on one side.

Then: remove the + 2.

Then: remove the 2.

Last: check.

Answer
x = 1

Your turn

Try this one yourself, then check:

x + 4x = 4 + 1x
Show the answer
x = 1

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