Question

thực hiện các phép tính sau :

2/5 . 5và1/4 - 2/7 . 3và1/4 

( 2và1/3 + 3và1/2 ) : ( -4va1/6 + 3va1/7 ) + 7va1/2

 

Answer 1

\(\frac{2}{5}\cdot5\frac{1}{4}-\frac{2}{7}\cdot3\frac{1}{4}\)

= \(\frac{2}{5}\cdot\frac{21}{4}-\frac{2}{7}\cdot\frac{13}{4}\)

= \(\frac{21}{10}-\frac{13}{14}\)

= \(\frac{41}{35}\)

\(\left(2\frac{1}{3}+3\frac{1}{2}\right):\left(-4\frac{1}{6}+3\frac{1}{7}\right)+7\frac{1}{2}\)

= \(\left(\frac{7}{3}+\frac{7}{2}\right):\left(\frac{-25}{6}+\frac{22}{7}\right)+\frac{15}{2}\)

= \(\frac{35}{6}:\frac{-43}{42}+\frac{15}{2}\)

= \(\frac{-245}{43}+\frac{15}{2}\)

= \(\frac{155}{86}\)