Question 87645
2 numbers that multiply to give 4 --> either 1x4 or 2x2


Added complication: the x^2 term has a 6 so either we have 6x1 or 3x2 there. We now need to mess around with these 2 pairings until we get 5.


3x2 and 1x4 could give us a 5 --> 3x1 and 2x4 could by having -3+8
no othere pairings give a 5


So (3x 4)(2x 1) is the order we need. We just need to figure out the signs. The 4 and 1 multiply to give -4 so we need 1 +ve and 1 -ve. So either:

(3x + 4)(2x - 1) or (3x - 4)(2x + 1)

Looking at the first version: -3x+8x --> +5x which is what we need, so this is the answer. The second version would give us -5x because the only difference is the order of the signs.


answer: (3x + 4)(2x - 1)


the more you do, the quicker/better you get.


cheers
Jon