Răspuns :

x-400=y+670=3200

x-400=y=3200-670

x-400=y=2530

x-400=2530

x=2530+400

x=2930

Răspuns:

a-400+670=3200

a-400=3200-670

a-400=2530

a=2530+400

a=2930

Verificare

2930-400+670=3200