a) 7*(-4)-1=-29
7*5-1=34
7*0-1=-1
b) 6-3=3
6-(-2)=8
6-0=6
c) 5*(9-5)=5*4=20
8*(9-8)=8*1=8
-3*(9-(-3))=-3*12=-36
d) 8-4*3=8-12=-4
8-4*(-3)=8-(-12)=20
8-4*0,25=8-1=7
