Steply

Simplify 8^(1/3)

Step by step, with the reason for every step · Rational exponents · Algebra 1

Step by step

The question

Question: work out 8^(1/3).

8^(1/3)

A fraction power has two jobs.

The bottom number, 3, says which root: the cube root.

The top number, 1, says which power.

a^(m/n) = (n√a)m

Careful!

The power is not times.

8 times 1/3 is a different number.

Careful: not 8^(1/3) = 8 × 13 ✗

1 Write it as a root

The bottom is 3, so it is the cube root of 8.

The top is 1: power 1 changes nothing.

= 3√8

∛8 is 2, because 2 × 2 × 2 is 8.

2 × 2 × 2 = 8

So 8^(1/3) = 2.

= 2

2 Check

Let's check: 2 times itself 3 times.

We get 8.

So the answer is right!

2 × 2 × 2 = 8

Let's look back.

First: write it as a root.

Last: check.

Answer
= 2

Your turn

Try this one yourself, then check:

Work out 16^(1/4)
Show the answer
2

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