y=3(x+5)(x-2)

Question

I'm suppose to simplify right?
There is no way to solve for the variables.

y=3(x+5)(x-2)
use the distributive property
y=3x+15(x-2)
y=3x+15x-30
y=18x-30

thanks for your help but the book says the answer is y =3xsquared + 9x-30

how did they get answer?