12
+ 18x - 12
Before we get started, notice that 12 and 18 are both divisible by 6. This will be helpful when factoring!
Part A:
factor out 6
6(2
+ 3x -2)
So I need to figure out 2 numbers that multiply together and make -2 (only -2 and 1 OR 1 and -2) and also notice that we have a coefficient of 2 on that x^2, so... honestly this is sort of a game of guess & check, but we will have 1 set of parentheses with + and another with - because the middle term is positive and the last term is negative.
Now rewrite:
6(2x-1)(x+2)
Part B:
Let's check by expanding:
6(2x-1)(x+2)
6(2
+4x-x-2)
Combine like terms
6(2
+3x-2)
Now multiply everything in parentheses times 6:
12
+18x-12
which was the original equation, so our factored equation is correct.