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Practice English Speaking&Listening with: División de radicales con variables (básico sin racionalización)

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We were asked to simplify

the given radical expressions.

A radical expression is not considered simplified

if there's a fraction under the radical

or if there's a radical in the denominator.

For the first example we have the square root of 100X

divided by five X.

The first step should always be to see

if the fraction under the radical will simplify.

100X divided by five X simplifies very nicely

because five X is a factor of 100X.

To show this, let's write 100X

as 20 times five X.

Notice in this form, we can see that

five X divided by five X will simplify to one

and therefore the radical simplifies

to the square root of 20,

but now we need to simplify the square root of 20

by identifying any perfect square factors of 20.

To do this, let's look at the prime factorization of 20,

which is two times two times five.

So the square root of 20 is equal to the square root

of two times two times five.

Notice here we have two factors of two,

which shows 20 contains the perfect square factor

of two squared or four.

Before simplifying,

let's write two times two as two squared.

This is equal to the square root of two squared times five

and the square root of two squared simplifies perfectly

to one factor of two.

The simplified expression is two square root of five.

Next we have the cube root

of 64X squared Y to the fifth

divided by the cube root of four Y squared.

Now this radical expression looks rather messy.

So what we'll do in this case is use the radical property

shown below in the opposite direction.

Notice the property indicates the X root of A

divided by the X root of B

is equal to the X root of the fraction A over B,

which means the quotient of these two cube roots

is equal to the cube root

of the fraction 64X squared Y to the fifth

divided by four Y squared.

In this form, we will now simplify the fraction

and then simplify the resulting cube root.

So we have the cube root of 64 divided by four

is equal to 16.

Then we have X squared.

Then we have Y to the fifth divided by Y to the second.

Remember, when dividing and the bases are the same,

we subtract the exponent.

So Y to the fifth divided by Y to the second

is equal to Y raised to the power of five minus two,

which equals Y cubed.

So this simplifies here

the cube root of 16X squared Y to the third.

Now to continue simplifying, because we have a cube root,

we look for perfect cube factors of the radicand.

Well the prime factorization of 16

is four factors of two.

So we have two times two times two times two.

Notice how here we have three equal factors of two

and we have X squared,

which does not contain any perfect square factors.

Let's go ahead and write X squared as X times X.

Then we have Y to the third,

which is equal to Y times Y times Y.

Notice here we have three equal factors of Y.

Let's write this one more time using exponents

before we simplify.

Let's write this as the cube root

of two cubed times two times the X squared,

which will not simplify, times Y cubed.

And again, here we have three equal factors of two

and three equal factors of Y.

The cube root of two cubed is equal to one factor of two.

The cube root of Y cubed is equal to one factor of Y

and we still have the cube root of two X squared.

This is the simplified radical expression

and because the index is odd,

there's no need for an absolute value.

I hope you found this helpful.

The Description of División de radicales con variables (básico sin racionalización)