We have the standard form f(x) = ax^2 + bx + c . This is called the ac method because we start by multiplying the coefficient a by c. An example will illustrate the method:- Factor 4x^2 + 4x - 3 ac = 4*-3 = -12 Now factor -12:- prime factors of -12 are -2*2*3 The middle term + 4x comes from adding 2 terms in x. We are aiming to get the middle term + 4x - so, from the factors, 2*3x - 2x looks a good bet So we write 4x^2 + 6x - 2x - 3 now we try to factor by grouping in this case its easier to see how to do this if we reverse the order of the 2 middle terms 4x^2 - 2x + 6x - 3 = 2x(2x - 1) + 3(2x - 1) 2x - 1 is common to both parts so we have (2x + 3)(2x - 1)
During my short teaching career I found quite a few pupils had problems with factoring these and this method is the one which most of them took to.
good job :)
Huh, nice work
This is called the *headphone* method :P
thats what my teacher told us . |dw:1438711610806:dw| looks like a headphone ? lol
yes that's a good way to remember it !
yeah that^^ nvm :) nice work!