2x-3a<7b 2x<3a+7b x<(3a+7b)/2 6b-3x<5a 3x>6b-5a x>(6b-5a)/3 由题意得 (6b-5a)/3且 (6b-5a)/3=5 (3a+7b)/2=22 即 6b-5a=15 (1) 3a+7b=44 (2) (1)*3: 18b-15a=45 (3) (2)*5: 15a+35b=220 (4) (3)+(4): 53b=265 b=5 (5) 把(5)代入(1)即得a=3 故 a=3 b=5