posted by mace on .
USE THE AC METHOD FACTORING 9+^2+5+-4 CAN SOME ONE SHOW ME THE STEP TO SOLVING THIS PROBLEM
9x^2 + 5x - 4
the AC method
Multiply the 9 times -4
You have -36
think of factors that will multiple to equal -36 but add to equal the middle number 5.
36 times -1 no
9 times -4 yes
Sometimes it takes awhile to find the right numbers.
Once you do, you write them and -4x + 9x
You replace the middle term with them.
9x^2 -4x + 9x - 4
Next, you factor by grouping
(9x^2 -4x) + (9x - 4)
Take out the common factor in each group.
x(9x-4) + 1(9x-4)
see the (9x-4)... you write that down once and get your other factor from what is left over (x+1)
FINAL ANSWER: (9x-4)(x+1)
Multiply those factors to check to be sure you are correct.