Expert: Lynn Houston - 4/3/2009

Question
Hi. I am a grade 8 student and I'm not to good with math.
We have a quiz tomorrow on Multi-step equations and I keep
forgetting how to do them.

The question is -
2(4x-3)-8=4+2x

It is only one of the questions on the study paper, but if
you could PLEASE explain to me where to start and how
exactly to do every step, that would seriously help me pass
this test. Thank you very much.

Cristina

Answer
First you multiply what's in the parenthesis by 2

2(4x-3)-8=4+2x
8x-6-8=4+2x  Combine the like terms on each side of the = sign
8x-14 = 4+2x  Now, you have to get the constants on one side and the variables on the others so add 14 to both sides and subtract 2x from both sides

8x-14+14-2x = 4+2x-2x+14
8x-2x = 4+14
6x = 18  In order to get the x all by itself, you have to divide both sides by 6

6x/6 = 18/6 or  x = 3

The trick to these is to combine like terms, get the variable on one side of the equation and then "undo" everything that has been done to the x (or variable).  So in the eq above, x had 14 subtracted, so you had to add it to both sides and it was multiplied by 6 so you had to divide by 6.