Answer:
The correct option is letter D.
Step-by-step explanation:
We have the following expression:
sqrt(y^3) + sqrt(9y^3) - 3y*sqrt(y)
We now that sqrt(a*b) = sqrt(a)sqrt(b)
Applying this rule, we have:
sqrt(y^3) + sqrt(9y^3) - 3y*sqrt(y)
sqrt(y^3) + 3sqrt(y^3) - 3y*sqrt(y)
Also we know that a*sqrt(b) = sqrt(b*a^2)
Applying this we have:
sqrt(y^3) + 3sqrt(y^3) - 3y*sqrt(y) = sqrt(y^3) + 3sqrt(y^3) - 3sqrt(y^3)
Then the result is:
sqrt(y^3) + 3sqrt(y^3) - 3sqrt(y^3) = sqrt(y^3) = y*sqrt(y)
The correct option is letter D.
