Срочнооо номер 47 а)..... Это пропорция, нужно найти х

Решите задачу:

$1)15,2*0,25=15 \frac{2}{10}* \frac{25}{100} =15 \frac{1}{5}* \frac{1}{4} = \frac{76}{5}* \frac{1}{4}= \frac{19}{5}$

$2)48,51:14,7=48 \frac{51}{100} :14 \frac{7}{10}= \frac{4851}{100} * \frac{10}{147} = \frac{33}{10}$

$3) \frac{19}{5} - \frac{33}{10}= \frac{38-33}{10} = \frac{5}{10}= \frac{1}{5}$

$4) \frac{1}{5} :x= \frac{1}{5x}$

$5) \frac{5}{66} :2 \frac{1}{2}= \frac{5}{66}* \frac{2}{5}= \frac{1}{33}$

$6) \frac{13}{44} - \frac{2}{11} = \frac{13-8}{44}= \frac{5}{44}$

$7) \frac{5}{44} - \frac{1}{33}= \frac{165-44}{1452} = \frac{121}{1452} = \frac{1}{12}$

$8) \frac{1}{12} *1 \frac{1}{5} = \frac{1}{12}* \frac{6}{5} = \frac{1}{10}$

$9)3,2+0,8=3 \frac{1}{5}+ \frac{4}{5}= \frac{16}{5}+ \frac{4}{5}= \frac{20}{5}=4$

$10)5,5-3 \frac{1}{4} = \frac{11}{2} - \frac{13}{4} = \frac{22-13}{4}= \frac{9}{4}$

$11)4* \frac{9}{4} =9$

$5x=9: \frac{1}{10}$

$5x=90$

$x=18$