x-3≥a--->x≥a+3
b-x≥-2--->x≤b+2
解集为x=2b+a+1---->
a+3=b+2
a+3=2b+a+1
解方程组得:
a=0
b=1
x-k≥a--->x≥k+a,即:x≥k
x+kx