3x2 + 7x - 6
Multiply the 3 and -6 together to get -18 .
What two numbers add to 7 and multiply to -18 ? → +9 and -2
So...we can split the middle term like this...
= 3x2 + 9x - 2x - 6 Now factor a 3x out of the first two terms.
= 3x(x + 3) - 2x - 6 Now factor a -2 out of the last two terms.
= 3x(x + 3) - 2(x + 3) Now factor a (x + 3) out of both remaining terms.
= (x + 3)(3x - 2)