A-4（B-（A+2B）/2）
=A-4B+2(A+2B)
=A-4B+2A+4B
=3A
依题意：A=a-2b+1 a=22/3 ,b=-7
3A=3(a-2b+1)
=3[22/3-2*(-7)]
=22+14*3
=22+42
=64