А)

[tex] \frac{1}{5}x = 15 [/tex]

[tex]5 \times \frac{1}{5}x = 5 \times 15 [/tex]

[tex]x = 75[/tex]

В)

[tex]6x = \frac{1}{9} [/tex]

[tex]6x \div 6 = \frac{1}{9} \div 6 [/tex]

[tex]x = \frac{1}{9} \times \frac{1}{6} [/tex]

[tex]x = \frac{1}{54} [/tex]

Г)

[tex]7y = - \frac{7}{8} [/tex]

[tex]7y \div 7 = - \frac{7}{8} \div 7 [/tex]

[tex]y = - \frac{7}{8} \times \frac{1}{7} [/tex]

[tex]y = - \frac{1}{8} [/tex]

Д)

[tex] \frac{3}{5}y = 10 [/tex]

[tex] \frac{5}{3} \times \frac{3}{5}y = \frac{5}{3} \times 1 0[/tex]

[tex]y = \frac{50}{3} [/tex]