Question

198+ х=485   у+(372-183)=507

Answer 1

198+Х=485                  у+(372-183)=507
Х=485-198                   у+189=507 
Х=287                         у=507-189
Проверка                    у=318
198+287=485              Проверка
                                  318+(372-183)=507
     

Answer 2

198+х=485
х=485-198
х=287
198+287=485
485=485

у+(372-183)=507
у=372-183=189
у=507-189
у=318
318+(372-183)=507
507=507