if you change all the variables to the given valuables, the new equation would be (-3 + -9) - (-2 - 2 x -9)
Solve what's in the parenthesis first. -3 + -9 is -12. -2 x -9 is -18, and -2 - -18 is 16. Then you do -12 - 16 and you get -28
-28 is the answer :D