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Cube Roots and Other Radicals

Reference > Mathematics > Algebra > Simplifying Radicals
 

Once you understand how to simplify square roots like
8x5
, it's only a short step to simplifying expressions like
3
54x4
.

The first step, as with square roots, is to find the prime factorization of 54, and then rewrite the cube root:

3
54x4
=
3
2 · 33  · x4

Now, we recognize that x has an exponent that's greater than 3, but is not a multiple of three. So we're going to rewrite it as a product of two factors, one of which is a perfect cube:

x4 = x3 · x1

This means:

3
2 · 33  · x4
=
3
2 · 33 · x3 · x1
=
3
33 · x3
 ·
3
2 · x
=
3x
3
2x

Let's try another. Simplify
5
64x8y4z14

Again, we do a prime factorization on 64:

5
64x8y4z14
=
5
26x8y4z14

We have several exponents greater than 5, so we need to do some rewriting:

5
25 · 21 · x5 · x3 · y4 · z10 · z4

5
25 · x5 · z10
 ·
5
2 · x3 · y4 · z4

2xz2
5
2x3y4z4

Questions

1.
Simplify
3
108
2.
Simplify
4
256
3.
Simplify
3
x5
4.
Simplify
3
8xy8
5.
Simplify
8
x16y25
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Simplifying Square Roots with VariablesSimplifying Square Roots with Variables
Combining Radical ExpressionsCombining Radical Expressions
 

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