a)
`38`$\frac{1}{5}$ `xx`$\frac{2}{7}$ - $\frac{2}{7}$ `xx` `52`$\frac{1}{5}$
`=`$\frac{2}{7}$ `xx`(`35`$\frac{1}{5}$ - `52`$\frac{1}{5}$ )
`=`$\frac{2}{7}$ `xx`($\frac{191}{5}$ - $\frac{261}{5}$ )
`=`$\frac{2}{7}$ `xx` (-${14}$)
`=` `-4`
b)
`6 - 3` (-$\frac{1}{3}$ $^{3}$) + `4`(-$\frac{1}{2}$)$^{2}$
`=``6 - 3` `xx` (-$\frac{1}{27}$ ) + `4``xx`-$\frac{1}{4}$
`=``6` - (-$\frac{1}{9}$) + `1`
`=`$\frac{64}{9}$
`\color{cyan}text{#nguyenthanhphat4240}`
