Bài 1
a) \(\frac{3}{5}.\frac{5}{4}-\frac{3}{5}.\frac{1}{4}\)
\(= \frac{3}{5}.(\frac{5}{4}-\frac{1}{4})\)
\(= \frac{3}{5}\)
b) \(\frac{4}{6}.\left ( \frac{-5}{7} \right ):\left ( \frac{-4}{6} \right )
\)
= \(\frac{4}{6}.\left ( \frac{-5}{7} \right ).\left ( \frac{6}{-4} \right )\)
\( =\frac{5}{7} \)
Bài 2 tìm x , biết
a) \(\frac{x}{5}=\left ( \frac{-7}{3} \right )\)
<=> \(x=\frac{5.-7}{3}=\frac{-35}{3}\)
b \(x- \frac{3}{10}=\frac{7}{15}.\frac{3}{5}\)
\(<=> x- \frac{3}{10}=\frac{7}{25}\)
\(<=> x=\frac{7}{25} + \frac{3}{10}=\frac{29}{50}\)
Chúc bạn học tốt!