The expression can be factored by using the X method or the multiplying method,
which is (3x+4)(x+2). A and B are 4 and 2, so A - B = 2. btw the multiplying method is where you multiply 8 by 3 and get 24, and 12*2=24 12+2=14,
3*4=12, so (3x+4) comes together. then the 2 is prime, so it goes on the other side. ( it's a little confusing at first but it gets better )