Answer:
Option C.
Step-by-step explanation:
We start with the expression:
[tex]\sqrt{y^3} + \sqrt{16*y^3} - 4*y\sqrt{y}[/tex]
where y > 0. (this allow us to have y inside a square root, so we don't mess with complex numbers)
We want to find the equivalent expression to this one.
Here, we can do the next two simplifications:
[tex]\sqrt{16*y^3} = \sqrt{16} \sqrt{y^3} = 4*\sqrt{y^3}[/tex]
And:
[tex]y*\sqrt{y} = \sqrt{y^2} *\sqrt{y} = \sqrt{y^2*y} = \sqrt{y^3}[/tex]
If we apply these two to our initial expression, we can rewrite it as:
[tex]\sqrt{y^3} + \sqrt{16*y^3} - 4*y\sqrt{y}[/tex]
[tex]\sqrt{y^3} + 4*\sqrt{y^3} - 4\sqrt{y^3} = \sqrt{y^3}[/tex]
Here we can use the second simplification again, to rewrite:
[tex]\sqrt{y^3} = y*\sqrt{y}[/tex]
So, concluding, we have:
[tex]\sqrt{y^3} + \sqrt{16*y^3} - 4*y\sqrt{y} = y*\sqrt{y}[/tex]
Then the correct option is C.
