algebra question?

Question

factor completely
3x^2 + x - 24

Answer 1

(3x - 8)(x + 3)

Answer 2

This is a quadratic, so let's use the formula:

(-1 +- sqrt(289))/6 = (-1 +- 17)/6 = 8/3, -3.
So the factors are (3 x - 8) (x + 3)

Another way:
We want (a x + b) (c x + d) = a b x² + (b c + a d) x + b d = the above.
Therefore, a b = 3, bc + ad = 1, and bd = -24.
Let a = 3 and c = 1, because they are either both positive or both negative, and one has to be three.
Now, try a few ways of factoring 24. When you get to 3 and -8,
you try b = 3 and d = 8, and get bc + ad = -21. Try the other way, and you get bc + ad = -1. Switch the signs on b and d, and they come to the correct answer.
(3 x - 8) (x + 3).

Answer 3

Using the quadratic equation, you can get the factors completely..
this is a complete square, so you can factor out the expressions: also you can trace back the reverse of the FOIL method..
(3x - 8) ( x + 3)
3x*x = 3x^2
9x - 8x = x
(-8)(3) = -24

Answer 4

first, divide the last term by the first term (24 / 3) that will give you 8. next, you have to arrange the numbers to satisfy the equation, remember that your middle term is positive and the last term is negative, therefore the signs are positive and negative for your factors:

(3x - 8)(x + 3)

Answer 5

3x^2 + x - 24
(3x - 8)(x + 3)

Answer 6

3x^2+x-24
(3x - 8)(x+3)

Answer 7

(3x - 8)(x + 3)

u use the (un) FOIL method. this can be checked by foiling it....3x * x = 3x^2, then 9x-8x = x , and -3 * 8 =-24. so u put it together, and u get 3x^2 + x - 24................................

or put it this way:

(3x - 8)(x + 3)
=3x^2 + 9x - 8x -24
=3x^2 + x - 24

Answer 8

(3x - 8)(x + 3) = 0
x = 8/3
x = -3

Answer 9

use the quadratic formula: