posted by kota .
Solve for c.
There can be no = sign within parentheses. What did you really man to write?
Also: Is the c meant to be in the denominator with the last 3?
Since + is shift=, I'll guess it's supposed to be
A = -3(a + b - 1/3 c)
-A/3 = a + b - 1/3 c
-(A/3 + a + b) = -c/3
c = A + 3a + 3b