metoda grafica:
a+b+c=132
a=3xb
b-c=13⇒b=c+13
c /........../
b /........../...+13./
a /........../...+13./........../...+13.//........../...+13./ }132
5 parti+4x13=132
5 parti+52=132
5 parti=132-52=80
1 parte=80:5
1 parte=16
1 parte=c=16
c=16
b=13+16=29
a=3x29=87
proba 87+29+16=132
algebric:
a+b+c=132
a=3xb
b-c=13⇒b=c+13
3x(c+13)+c+13+c=132
3xc+39+c+13+c=132
5xc+52=132
5xc=132-52
5xc=80
c=80:5
c=16
b=16+13=29
a=3x29=87
