help!! 2x(x is to the 2nd power)-5x-12 , factor??show steps!!?

Answer 1

bpi guy has got it correct...for most it's an educated guess and check method...other methods usually take more time

Answer 2

2x^2 - 5x-12 . The 12 is negative so put in a + and a - into the factors. From just the 2x^2 you get:
(2x + _)(x - _)
To find the blanks use factors of 12 (ie: 2,6 or 3,4 or 1,12); since the middle number is odd, you want a pair of factors with an odd and an even number (ie 3,4 or 1, 12). The 12 is too large so try 3, 4.
(2x + 3)(x - 4) 2x+3=0 2x=-3 x=-3/2
x-4=0 x=4 Your two factors are x=-3/2 and x=4
Proof Use the foil method on (2x + 3)(x - 4) =2x^2 -8x + 3x - 12 = 2x^2 -5x-12

Answer 3

So, in general if the equation were all even numbers, I would pull out a common multiple of two. But since that 15 is in there, you know that 2x^2 has to be in there.

Using that, here's where we start: We know one factor has to start with 2x, and the other has to be x. Also, since the last number is negative, we know that the signs alternate:

(2x + __) (x - __) OR (2x - __)(x + __)

Then we just guess and check which numbers that can make 12 can also get you -5 when you double one of them and subtract from the other.

Factors of 12 are: 12 and 1; 2 and 6; 3 and 4. That's it, that's all of them, so let's guess and check:

Looking at it, you can see that if you double four, and subtract three from it, you get five. By doubling four, that means the four goes in the parentheses that DOESN'T have the 2x:

(2x + 3) (x - 4) OR (2x - 3)(x + 4)

And then since you want -5 instead of positive five, you pick:

(2x + 3) (x - 4) = 2x^2 -5x -12

Answer 4

ok

this is how I was taught

axc = 2x-12 = -24

factor -24

what 2 factors of 24 add to -5 and multiply to -24?

-8 and 3

so

2x^2 - 8x + 3x - 12

group

(2x^2 - 8x) + (3x - 12)

factor each

2x (x-4) + 3 (x-4)

factor

(2x+3)(x-4)

x = -3/2
x= 4



hoped I explained it good

Answer 5

i'm going to assume you recommend (2/5)x - 6 = 12 (2/5)x - 6 = 12 (2/5)x + (- 6) = 12 (definition of subtraction) [(2/5)x + (- 6 )] + 6 = 12 + 6 (addition belongings of =) [(2/5)x + (- 6 )] + 6 =18 simplification (2/5)x + [(- 6 ) + 6] = 18 {associative belongings of addition} (2/5)x + 0 = 18 {axiom of additive inverse} (2/5)x = 18 {idenity of addition} [5/2][(2/5)x ] = 5/2(18 ){x belongings of =} [5/2(2/5)]x = 5/2(18) { assocaitive belongings of x} 1x = 5/2(18) axiom of multiplicative inverse 1x= 40 5 simplification x = 40 5 {id for multiplication} This sounds long winded, yet while by applying coach all steps skill you're required to coach the axioms of genuine numbers used, that's the answer.

Answer 6

2x^2 - 5x - 12 = (2x + 3)(x - 4)