Question

How do you factor this?

Answer 1

x^3 - 4x^2 + 3x - 12

Answer 2

I got to factoring the first 3 terms x(x^2-4x+3)+12

Answer 3

What next

Answer 4

@kevincourtes long division, help him,

Answer 5

@LangstonK wrong way friend

Answer 6

@LangstonK (x^2+3)(x-4)

Answer 7

show your work, @kevincourtes

Answer 8

Kevin how do you get to there? I already know the answer. just not how to get there

Answer 9

@kevincourtes knock knock

Answer 10

Mind explaining, loser?

Answer 11

Think hes not there

Answer 12

hey, not know how to show? ask me for help?

Answer 13

sorry?

Answer 14

Is there a way without synthetic division?

Answer 15

he is off line. now, I guide you horner's rule

Answer 16

want to know?

Answer 17

ok. because synthetic division is long and repetitive and i dont want to do it during an exam

Answer 18

start at the last number is -12 you have some products of -12
-12 = 12*(-1)
-12 = (-12)*1
-12= 4*(-3)
-12=3 * (-4)
-12= (-2)*6
-12= 6* (-2)
If you are lucky, you can get the correct answer at the first time you try, if not, you must try one by one. My experience tells me that I should pick the couple which I can calculate in my head and know it is the right answer, for example, if i pick 12 * (-1) it means -1 must be one of the root, I replace x =-1 into the original function and get (-1)^3 +4 (-1)^2 +3(-1)-12 = -12 (not =0) so -1 cannot be a root, get rid of,
do the same you will see only 4* (-3) or (-4)*3 might be right. I pick 4 to try
continue?

Answer 19

no shortcut, friend, math need proof and you have to master it.

Answer 20

So just find the one pair of multiples that equal 0 when plugged x?

Answer 21

What happens when i find the pair?

Answer 22

not that simple. horner's rule is not apply yet.