Simplify the following expression completely, where [tex]\( x \geq 0 \)[/tex]:

[tex]\[ x \sqrt{5 x y^4} + \sqrt{405 x^3 y^4} - \sqrt{80 x^3 y^4} \][/tex]

A. [tex]\( x y^2 \sqrt{5 x} + x y^2 \sqrt{405 x} - x y^2 \sqrt{80 x} \)[/tex]

B. [tex]\( 6 x y^2 \sqrt{5 x} \)[/tex]

C. [tex]\( -3 x y^2 \sqrt{5 x} + x y^2 \sqrt{405 x} \)[/tex]

D. [tex]\( 6 x y \sqrt{5 x y^2} \)[/tex]



Answer :

Let's carefully simplify the given mathematical expression step-by-step. The expression we need to simplify is:

[tex]\[ x \sqrt{5 x y^4} + \sqrt{405 x^3 y^4} - \sqrt{80 x^3 y^4} \][/tex]

### Step 1: Simplify each term inside the square root

#### Term 1: [tex]\( x \sqrt{5 x y^4} \)[/tex]

For the first term:

[tex]\[ x \sqrt{5 x y^4} \][/tex]

Notice that [tex]\( y^4 \)[/tex] can be written as [tex]\( (y^2)^2 \)[/tex]. So, we rewrite the term inside the square root as:

[tex]\[ x \sqrt{5 x y^4} = x \sqrt{5 x (y^2)^2} \][/tex]

We can take [tex]\( y^2 \)[/tex] out of the square root:

[tex]\[ = x \cdot y^2 \cdot \sqrt{5 x} \][/tex]

So, the simplified first term is:

[tex]\[ x y^2 \sqrt{5 x} \][/tex]

#### Term 2: [tex]\( \sqrt{405 x^3 y^4} \)[/tex]

For the second term:

[tex]\[ \sqrt{405 x^3 y^4} \][/tex]

Rewrite the term inside the square root to see how we can simplify:

[tex]\[ \sqrt{405 x^3 y^4} = \sqrt{405 x^3 (y^2)^2} \][/tex]

We can take [tex]\( y^2 \)[/tex] outside of the square root, and also factorize 405 as [tex]\( 9 \cdot 45 \)[/tex]:

[tex]\[ = y^2 \sqrt{405 x^3} = y^2 \sqrt{9 \cdot 45 x^3} \][/tex]

Since [tex]\( \sqrt{9} = 3 \)[/tex]:

[tex]\[ = y^2 \cdot 3 \sqrt{45 x^3} \][/tex]

Notice that inside the square root, [tex]\( 45x^3 \)[/tex] simplifies since [tex]\( x^3 \)[/tex] can be written as [tex]\( x \cdot x^2 \)[/tex]:

[tex]\[ = y^2 \cdot 3 \cdot x \sqrt{45 x} = y^2 \cdot 3 x \sqrt{45 x} \][/tex]

#### Term 3: [tex]\( \sqrt{80 x^3 y^4} \)[/tex]

For the third term:

[tex]\[ \sqrt{80 x^3 y^4} \][/tex]

Similar to the previous terms, rewrite the term inside the square root:

[tex]\[ \sqrt{80 x^3 y^4} = \sqrt{80 x^3 (y^2)^2} \][/tex]

Take [tex]\( y^2 \)[/tex] outside of the square root and factorize 80 as [tex]\( 16 \cdot 5 \)[/tex]:

[tex]\[ = y^2 \sqrt{80 x^3} = y^2 \sqrt{16 \cdot 5 x^3} \][/tex]

Since [tex]\( \sqrt{16} = 4 \)[/tex]:

[tex]\[ = y^2 \cdot 4 \sqrt{5 x^3} \][/tex]

And simplify inside the square root:

[tex]\[ = y^2 \cdot 4 \cdot x \sqrt{5 x} = 4 x y^2 \sqrt{5 x} \][/tex]

### Step 2: Combine the simplified expressions

Now, combine the terms:

[tex]\[ x y^2 \sqrt{5 x} + 3 x y^2 \sqrt{45 x} - 4 x y^2 \sqrt{5 x} \][/tex]

Factor out the common term [tex]\( x y^2 \)[/tex]:

[tex]\[ x y^2 \left( \sqrt{5 x} + 3 \sqrt{45 x} - 4 \sqrt{5 x} \right) \][/tex]

Simplify the inside of the parentheses:

[tex]\[ \sqrt{5 x} - 4 \sqrt{5 x} = -3 \sqrt{5 x} \][/tex]

Thus, it now simplifies to:

[tex]\[ x y^2 \left( -3 \sqrt{5 x} + 3 \sqrt{45 x} \right) \][/tex]

Use [tex]\( \sqrt{45 x} = \sqrt{9 \cdot 5 x} = 3 \sqrt{5 x} \)[/tex]:

[tex]\[ = x y^2 ( -3 \sqrt{5 x} + 3 \cdot 3 \sqrt{5 x}) = x y^2 (-3 \sqrt{5 x} + 9 \sqrt{5 x}) \][/tex]

Simplify again:

[tex]\[ = x y^2 (6 \sqrt{5 x}) \][/tex]

So, the fully simplified expression is:

[tex]\[ = 6 x y^2 \sqrt{5 x} \][/tex]

Therefore, the simplified expression is:

[tex]\[ 6 x y^2 \sqrt{5 x} \][/tex]