Răspuns :
a=4b
c=3b
a,b,c=?
a-b=12 => a=b+12
b+12=4b
12=4b-b
12=3b => b=12:3 => b=4
a=4x4 => a=16
c=3x4 => c=12
c=3b
a,b,c=?
a-b=12 => a=b+12
b+12=4b
12=4b-b
12=3b => b=12:3 => b=4
a=4x4 => a=16
c=3x4 => c=12
x=4y ; z=3y ;x-y= 12; y=12+x ; x= 4(12+x) ; x=48+4x ;3x=48; x=19 ;19-y=12;y=7; z=21