6a+11a = 17-11b-2b = -1313a-4a+17b-56 = 9a+17b-50.2x-0.2x+1.7y-0.2c = 1.7y-0.21.3c+2-0.2-1.2-0.2c = 1.3c-0.4-0.2c = 1.1c-0.4
6a+11a = 17
-11b-2b = -13
13a-4a+17b-56 = 9a+17b-5
0.2x-0.2x+1.7y-0.2c = 1.7y-0.2
1.3c+2-0.2-1.2-0.2c = 1.3c-0.4-0.2c = 1.1c-0.4