Решите пожалуйста!!!!!!!!!!!

А)
$(4.479 - 3x) \div 0.06 + 6.4 = 80 \\ (4.479 - 3x) \div 0.06= 80 - 6.4 \\ (4.479 - 3x) \div 0.06 = 73.6 \\ 4.479 - 3x = 73.6 \times 0.0 6 \\ 4.479 - 3x = \frac{736}{10} \times \frac{6}{100} \\ 4.479 - 3x = \frac{184}{5} \times \frac{3}{25} = \frac{552}{125} = \frac{4416}{1000} \\ 4.479 - 3x = 4.416 \\ 3x = 0.063 \\ x = 0.021$
б)
$8.36 - 5.36 \div (0.2x + 0.47x) = 7.56 \\ 8.36 - 5.36 \div 0.67x = 7.56 \\ 5.36 \div 0.67x = 0.8 \\ 0.67x = \frac{5.36}{0.8} = 6.7 \\ x = 10$