Уравнение. (( 2 4/7 - 1 2/3) + 5/21) * х = 8

Решите задачу:

$(( 2 \frac{4}{7} - 1 \frac{2}{3} ) + \frac{5}{21} ) * x = 8 \\ \\ \\ (( 2 \frac{12}{21} - 1 \frac{14}{21} ) + \frac{5}{21} ) * x = 8 \\ \\ \\ ( 2 \frac{12}{21} + \frac{5}{21} - 1 \frac{14}{21} ) * x = 8 \\ \\ \\ 1 \frac{12+5-14}{21} *x=8 \\ \\ \\ 1 \frac{3}{21} *x=8 \\ \\ \\ 1 \frac{1}{7} *x=8 \\ \\ \\ x=8 :1 \frac{1}{7} \\ \\ \\ x=8* \frac{7}{8} \\ \\ \\ x=7$