Steply

Simplify (3/x^2)/(9/x)

Step by step, with the reason for every step · Complex fractions · Algebra 2

Step by step

The question

Question: simplify this fraction.

On top: 3/x².

At the bottom: 9 over x.

A fraction with fractions inside is called a complex fraction.

3x29x

1 Find the common bottom

The small fractions have bottoms x² and x.

The smallest thing they all go into is x².

small bottoms: x², x
common bottom: x2

2 Times x² on top and bottom

x² over x² is 1.

Times 1 does not change the value.

x2x2 = 1

We multiply the top and the bottom by x².

Then the small fractions go away.

= x2 × (3x2)x2 × (9x)

3 Multiply every part

Every part times x².

x² times 3/x²: the bottom x² goes into x², so we get 3.

x² times 9/x: the bottom x goes into x², so we get 9x.

x2 × 3x2 = 3
x2 × 9x = 9x

So we get 3/9x.

No more small fractions!

= 39x

4 Simplify

Every part, on the top and the bottom, can be divided by 3.

So we divide the top and the bottom by it.

÷ 3: 3 → 1
÷ 3: 9x → 3x

So the answer is 1/3x.

= 13x

One more thing: no bottom can be 0.

So x can't be 0.

x ≠ 0

5 Check

Let's check with a number: x = 2.

In the question, the long way: the top is 3/4, the bottom is 9/2.

x = 2: top 34 = 34, bottom 92 = 92

Top divided by bottom: 1/6.

question: 34 ÷ 92 = 16

Our answer with x = 2 gives 1/6 too.

It works!

answer: 13(2) = 16

Let's look back.

First: find the common bottom.

Then: times x² on top and bottom.

Then: multiply every part.

Then: simplify.

Last: check.

Answer
= 13x

Your turn

Try this one yourself, then check:

simplify (4x2) ÷ (2x)
Show the answer
2x

More from Complex fractions

The whole lesson: Complex fractions →