having trouble on 1 problem on multi-step equations?

Question

-x-2=3x+5

-3x   -3x

2x-2=5
   +2  +2

2x/2=7/2

x=7/2

But appareantly this answer is wrong the right answer is -7/4 how come?  I don't understand? i thought -x-3x= -2x not 4x.. I thought you had to do the opposite which is subtract not add.

Tommy · Accepted Answer

-x - 2 = 3x + 5
-4x = 7
x = -7/4

your work :

-x-2=3x+5

-3x -3x

2x-2=5  <----- here is the problem -x - 3x is not +2x it's -4x. (ie -1 - 3 = -4)
+2 +2

2x/2=7/2

x=7/2

you did the steps correctly. you just forgot to bring down the negative sign with that first x. Then did a arithmetic error on top of it x - 3x would have been -2x not 2x.

edit:
"Thank anisse for trying but, I'm asking for the explanation for that answer. I know the answer is -7/4 but i don't understand why. I thought you had to subtract -x from -3 to give you -2. not add it"

Your right you need to subtract 3x from -1x. But your going to end up deeper in the negative range. You went the wrong way and added 3x to a -x. Hope this helps

Anonymous · Answer

-1x-2=3x+5
Add 2 to each side.
-1x=3x+7
subtract 3x from each side
-4x=7
divide each side by -4
-7/4
-4 doesn't go into 7 perfectly without it being a fraction. I don't know where you went wrong, just put -4 in the denominator making it -7/4

? · Answer

-x-2=3x+5
-3x  -3x
-4x-2=5
+2  +2
-4x=7
-4x/-4=7/-4
x=-7/4

having trouble on 1 problem on multi-step equations?

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