{ −(c−1)−3(c−2)≥5c, 2c+7≤11−(c−3). ​

−(c−1)−3(c−2)≥5c: −c + 1 - 3c + 6 ≥ 5c -4c + 7 ≥ 5c 7 ≥ 9c c ≤ 7/9

2c+7≤11−(c−3): 2c + 7 ≤11 - c + 3 3c ≤ 7 c ≤ 7/3