Question

Calculeza a b c:
(a+b)xc=81
a+b=9
a x c= 18

Answer 1

$(a+b)*c=81 \\ a+b=9 \\ a * c= 18 \\ 9c=81=\ \textgreater \ c=81:9=\ \textgreater \ c=9 \\ 9a=18=\ \textgreater \ a=18:9=\ \textgreater \ a=2 \\ b=9-2=\ \textgreater \ b=7$