7) Factor 3x² - 12
So, look at those 2 numbers, and see what they both have in common.
They are both divisible by 3! So, basically you divide 3x² and -12 with 3.
3(x² - 4)
It would be factorized like that because if you multiply 3 by x², you would get 3x², and if you multiplied 3 with -4, you would get -4.
~Hope I helped!~
