Answer
$3x^2(x+2)(x-5)$
Work Step by Step
First, pull out the greatest common factor $3x^2$. Inside the parentheses, use trial and error to get two terms that equal the third term when multiplied and also add up to the second term.
$3x^4-9x^3-30x^2$
$3x^2(x^2-3x-10)$
$3x^2(x+2)(x-5)$