with the b2+b- 12 your gonna want to do this
b2+b-12
b2+4b-3b-12
which is the sum product
after doing that you wanna common the factors from the two pairs. Which is b2+4b-3b-12 then you do you parentheses around b(b+4)-3(b+4) just like that after you do that then you rewrite it in factored form b(b+4)-3(b+4) you then want to rewrite it to this (b-3)(b+4) after that your solution will be (b-3)(b+4) for the first one.