48a+25a+7=443; 4(9+7х)+21=393

48а+25а+7=443
48а+25а=443-7
(48+25)а=436
73а=436
а=436:73
а=5,9

48а+25а+7=443; 73а=443-7; 73а=436; а=436:73; а=5,97
4(9+7х)+21=393; 36+28х=393-21; 28х=372-36; 28х=336; х=336:28; х=12