Răspuns :
a-b=15
a+12 = 4b
c=3/8 a+7
a = 15 +b
15+ b +12=4b
3b=27
b=9
a=15+9=24
c = 3*24:8+7
c = 9+7
c= 16
a+12 = 4b
c=3/8 a+7
a = 15 +b
15+ b +12=4b
3b=27
b=9
a=15+9=24
c = 3*24:8+7
c = 9+7
c= 16
x-y=15
x+12=4y =>x-4y=-12 |x-1
_____________
x-y=15
-x+4y=12
3y=27
y=9
x-9=15 =>x=24
c= (3/8)*24 +7 =16
x+12=4y =>x-4y=-12 |x-1
_____________
x-y=15
-x+4y=12
3y=27
y=9
x-9=15 =>x=24
c= (3/8)*24 +7 =16