Răspuns :
(56:a+16):5 =13-9
=(56:a+16)::5=4
=56:a+16) =4x5
=56:a+16 =20
=56:a =20-16
=56::a =4
a =56:4
a =14
=(56:a+16)::5=4
=56:a+16) =4x5
=56:a+16 =20
=56:a =20-16
=56::a =4
a =56:4
a =14