Next we will simplify a cube-root radical whose radicand contains a
variable.
We will use a procedure similar to the one we used to simplify square-root
radicals. However, when we simplify a cube-root radical, we divide the
exponent of the variable by 3 (instead of 2).
Here are some examples.
If x is any real number, then:
since
x · x · x = x3
since
x4 · x4
· x4 = x12
Notice that
since
x9 · x9
· x9 = x27
Notice that
In each example, the exponent of the variable in the simplified expression
is one-third the exponent of the variable in the radicand.
Be careful:
If the power of x in the radicand is not a multiple of 3, we rewrite the
radicand as a product where one of the factors has a power that is a
multiple of 3 and the other factor is x1 or x2.
For example, let’s simplify
Write x14 as x12
· x2.
Notice that 12 is a multiple of 3.
Write as the product of two radicals.
Simplify.
So,
Example
Simplify:
Solution
Factor the radicand, using perfect
cube factors when possible.