Question

thực hiện phép tính bằng cách hợp lí nhất:
a)\(\dfrac{5}{3}+\left(\dfrac{-2}{7}\right)-\left(-1,2\right)\)                                            b)\(\dfrac{-4}{9}+\left(\dfrac{-5}{6}\right)-\dfrac{17}{4}\)

 

Answer 1

a)\(\frac{5}{3}\)+ \(\left(\frac{-2}{7}\right)\)-(-1,2)

=\(\frac{5}{3}+\left(\frac{-2}{7}\right)+\frac{6}{5}\)                                          

=\(\frac{175+\left(-30\right)+126}{105}\)

=\(\frac{271}{105}\)

b) \(\frac{-4}{9}+\frac{-5}{6}-\frac{17}{4}\)

=\(\frac{-16+\left(-30\right)-153}{36}\)

=\(\frac{-199}{36}\)

Answer 2

\(\frac{5}{3}+\left(\frac{-2}{7}\right)-\left(\frac{-6}{5}\right)\)

=\(\frac{-2}{7}-\left(\frac{5}{3}+\frac{-6}{5}\right)\)

=\(\frac{-79}{105}\)\(\frac{-2}{7}-\frac{7}{15}\)