I'll show you how to solve for x.
1. 4x + 13 = 29
First, subtract 13 from both sides of the equals sign to get rid of the "+13"
4x + 13 - 13 = 29 - 13
(13 - 13 = 0) (29 - 13 = 16)
4x + 0 = 16
4x = 16
Now, "4x" is the same thing as "4 times x". If you have 4 x's, what do you do to get only one x? divide by 4.
You want too divide both sides of the equal sign by 4.
You can add, subtract, multiply etc. whatever you want as long as you do it to both sides of the equals sign.
4x = 16
4x / 4 = 16 / 4
x = 4.
Now just do this for each question. It doesn't have to be x by the way, this method works for any variable. (If a question doesn't have a "+" anything, just skip straight to dividing to isolate the variable.)
1. x = 4
2. m = 7
3. d = 8
4. d = 10
5. n = 4
6. x = 10
7. x = 5
8. x = 8
9. r = 6
10. p = 9
11. g = 3
12. s = 8.