Question

Which off the following expressions is equal to -3x^2-12

A. (-3x+2i)(x-6i)
B. (-3x-6i)(x+2i)
C. (-3x-6i)(x+2i)
D. (-3x-4i)(x-3i)

Answer 1

B. (-3x-6i)(x+2i)

C. (-3x-6i)(x+2i)

Since they are the same answer choice. Should be (-3x-6i)(x-2i) should be the correct answer.

Explanation:

The polynomial -3x^2-12 can be factored using GCF into -3(x^2+4).

x^2+4 is a sum of squares and factors into the form (x+ai)(x-ai).

x^2+4 factors into (x+2i)(x-2i).

We put them together and have -3(x+2i)(x-2i) = (-3x-6i)(x-2i)