d=b5-b3=32-8=24:2=12
b2=8-12=-4
b1=(-4)-12=-16
b3=8
b4=8+12=20
b5=32
b6=32+12=44
b7=44+12=56
b8=56+12=68
4<a<7 |*2 3<b<5 |*-5
8<2a<14 -15>-5b>-25
-25<-5b<-15
8-25<2a-5b<14-15
-17<2a-5b<-1