Question

Factor completely. 9x4 + 12x3 – 45x2 – 60x

Answer 1

The answer is C if not sorry

Answer 2

Answer:  The correct option is

(C) $3x(x^2-5)(3x+4).$

Step-by-step explanation:  We are given to completely factor the following bi quadratic expression :

$E=9x^4+12x^3-45x^2-60x~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

Since the given expression does not contain the constant term, so we will take out the x-term common and then will try to factorize the remaining cubic expression.

The factorization of expression (i) is as follows :

$E\\\\=9x^4+12x^3-45x^2-60x\\\\=3x(3x^3+4x^2-15x-20)\\\\=3x(x^2(3x+4)-5(3x+4))\\\\=3x(x^2-5)(3x+4).$

Thus, the required factored form of the given expression is $3x(x^2-5)(3x+4).$

Option (C) is CORRECT.