# How do you simplify #3y sqrt (4y^3) - sqrt (16y^4) + sqrt( 18y^3)#?

##### 1 Answer

Before doing any manipulations, let's determine the domain of this expression.

The only "restrictive" operation here is an operation of the square root that is defined in the field of *real numbers* only for non-negative arguments.

So, the domain is determined by an inequality

Now we can simplify this expression using a simple transformation that is true for non-negative numbers:

Using this, notice that

Combining these expression with their corresponding coefficients, produces: