4. 9,54 − 4,74 : (0,3x + 0,49x) = 8,94

\[9.54-\frac{4.74}{0.3x+0.49x}=8.94\]

\[\frac{4.74}{0.79x}=9.54-8.94=0.6\]

\[0.79x=4.74:0.6=7.9,\quad x=10\]

Проверка: \(9.54-4.74:(0.3\cdot10+0.49\cdot10)=9.54-4.74:7.9=8.94\).

Ответ: \(x=10\).