How do you factor 12x2+60x+75?

1 Answer
Oct 30, 2016

12x2+60x+75=3(2x+5)2

Explanation:

Note that all of the terms are divisible by 3, so separate that out as a scalar factor first:

12x2+60x+75=3(4x2+20x+25)

Next note that 4x2=(2x)2 and 25=52 are both perfect squares. So do we have a perfect square trinomial?

Let's try:

(2x+5)2=(2x)2+2(2x)(5)+52=4x2+20x+25

...matching our parenthesised quadratic.

So putting it all together we have:

12x2+60x+75=3(2x+5)2