10. 10.5(2 – 5x) – 7(4x - 1) = 6x-42

Решим уравнение: \begin{align*} 10.5(2 - 5x) - 7(4x - 1) &= 6x - 42 \\ 21 - 52.5x - 28x + 7 &= 6x - 42 \\ 28 - 80.5x &= 6x - 42 \\ -80.5x - 6x &= -42 - 28 \\ -86.5x &= -70 \\ x &= \frac{-70}{-86.5} \\ x &= \frac{700}{865} \\ x &= \frac{140}{173} \end{align*} Ответ: x = 140/173