3(x+2)-2(x-1)=7

I assume that you are solving for x.

1. remove the brackets by multiplying out the terms, for example
3(x+2)=3x+6

2. normally you would group the like terms together; so collect the x terms and the number terms together on the LHS.

3. rearrange so that the x terms are on one side and the number terms on the other side of the =

Does this help?