Question 52793
3+x-2(-4)=7-(-13) =        (multiply -2 and (-4) and change the double - to +)
3+x+8=7+13 =               (add 7+13 and 3+8)
11+x=20 =                  (Subtract 11 from 20)

x=9

;) there you go!
-antsinmypants!