After you simplify how do know if you should add or subtract?

Question

6x+-2+2x=-2+4x+8

Answer 1

Hi Terria--

 

After you simplify, the idea will be to get rid of the x term on one side and the numerical term on the other, so that you are left with an x term on one side equaling a numeric on the other.

 

So, if you are trying to get rid a positive term on one side, subtract that term, which you then have to do from the other side as well.

 

If you are trying to get rid of a negative term on one side, add it to that side, and then you'll have to add it to the other side as well. ("Whatever you do to one side, you have to do to the other.")

 

So:

 

6x + -2 + 2x = -2 + 4x + 8 simplifies to:

 

8x - 2 = 4x + 6

 

On both sides, ADD 2 (to erase the -2) and SUBTRACT 4x (to erase the + 4x), and you get:

 

4x = 8, so

 

x = 2

 

Plug into both original equations to see if it checks. (Hint: it does!)

 

Matt in NY