To factor: 8x²-22x+5 Multiply the 8 by the 5 ignoring signs. Get 40 Write down all the ways to have two positive integers which have product 40, starting with 40*1 40*1 20*2 10*4 8*5 Since the last sign in 8x²-22x+5 is +, ADD them, and place the SUM out beside that: 40*1 40+1=41 20*2 20+2=22 10*4 10+4=14 8*5 8+5=13 Now, again ignoring signs, we find in that list of sums the coefficient of the middle term in 8x²-22x+5 So we replace the number 22 by 20+2 8x²-22x+5 8x²-(20+2)x+5 Then we distribute to remove the parentheses: 8x²-20x-2x+5 Factor the first two terms 8x²-20x by taking out the greatest common factor, getting 4x(2x-5) Factor the last two terms -2x+5 by taking out the greatest common factor, -1, getting -1(2x-5) So we have 4x(2x-5)-1(2x-5) Notice that there is a common factor, (2x-5) 4x(2x-5)-1(2x-5) which we can factor out leaving the 4x and the -1 to put in parentheses: (2x-5)(4x-1) To see a couple of other examples just like that using the AC method, go here: http://www.algebra.com/my/change_this_name32371.lesson?content_action=show_dev Edwin