Question

a+b=54
b+c=72
c+d=91

a+3*b+5*c+3*d/a+d=un cat si un rest

Answer 1

cumva asa vine?
a+b=54⇔ b=54-a si a=54-b
b+c=72⇔ c=72-a si b=72-c
c+d=91⇔ d=91-c 

a+3b+5c+3d/ a+d=
a+3(54-a)+5c+3d/a+d=
a+162-3a+5c+3d/a+d=
-2a+162+5c+3d/a+d=
-2a+162+5c+3(91-d)/a+d=
-2a+162+5c+273-3c/a+d=
-2a+435+2c/a+d=
-2a+435+2(72-b)/a+d=
-2a+435+144-2b/a+d=
-2a-2b+579/a+d=
-2(a+b)+579/a+d=
-2x54+579/a+d=
-108+579/a+d=
471/a+d=
471/54-b+91-c=
471/54-(72-c)+91-c=
471/54-72+c+91-c=
471/73⇔471:73=6 rest 33
              438
                33