Răspuns :
a-b=95
a=bx3+15
bx3+15-b=95
3b+15-b=95
3b-b=95-15
2b=80
b=80:2
b=40
a=3x40+15
a=120+15
a=135
a=bx3+15
bx3+15-b=95
3b+15-b=95
3b-b=95-15
2b=80
b=80:2
b=40
a=3x40+15
a=120+15
a=135