Номер 14?как решить срочно

Решите задачу:

$x+ \frac{4}{15}+ \frac{7}{15}=1 \\ \\ x+ \frac{11}{15}= \frac{15}{15} \\ \\ x= \frac{15}{15}- \frac{11}{15} \\ \\ x= \frac{4}{15}$

$\frac{15}{29}-y=1- \frac{11}{29} \\ \\ -y= \frac{29}{29}- \frac{11}{29}- \frac{15}{29} \\ \\ -y= \frac{3}{29} \\ \\ y=- \frac{3}{29}$

$1-y= \frac{16}{21}- \frac{8}{21} \\ \\ \frac{21}{21}-y= \frac{8}{21} \\ \\ -y= \frac{8}{21}- \frac{21}{21} \\ \\ -y=- \frac{13}{21} \\ \\ y= \frac{13}{21}$