Đáp án:
Giải thích các bước giải:
a) $x(-\frac{3}{8})=\frac{2}{5}\\\Leftrightarrow x=\frac{2}{5}\div (-\frac{3}{8})=-\frac{15}{16}$
b) $\frac{3x}{5}-\frac{1}{5}=\frac{4}{5}\\\Leftrightarrow \frac{3x}{5}=1\\\Leftrightarrow x=\frac{5}{3}$
c) $\frac{3}{5}\div x=-\frac{1}{5}\\\Leftrightarrow x=\frac{3}{5}\div (-\frac{1}{5})=-3$
d) $\frac{4}{7}+\frac{5}{7}\div x=1\\\Leftrightarrow \frac{5}{7}\div x=\frac{3}{7}\\\Leftrightarrow x=\frac{5}{3}$
f) $x\div \frac{4}{7}=-\frac{5}{2}\\\Leftrightarrow x=-\frac{5}{2}\times \frac{4}{7}=-\frac{10}{7}$
g) $\frac{5}{8}\times x+\frac{2}{5}=\frac{1}{5}\\\Leftrightarrow \frac{5}{8}x=-\frac{1}{5}\\\Leftrightarrow x=-\frac{8}{25}$
h) $\frac{7}{5}\div x+\frac{11}{7}=\frac{18}{7}\\\Leftrightarrow \frac{7}{5}\div x=1\\\Leftrightarrow x=\frac{7}{5}$
