[tex]-^{4)}\frac57+^{7)}\frac54=-\frac{5*4}{7*4}+\frac{7*5}{4*7}= \frac{-20+35}{28}=\frac{15}{28} \\ \\ -1,4*(-\frac57)= -\frac{14}{10}^{(2}*(-\frac57)= -\frac{\not7}{\not5}*(-\frac{\not5}{\not7})=1 \\ \\ -\frac57:\frac54=-\frac{\not5}{7}*\frac{4}{\not5}=-\frac47 \\ \\ Numerele~reciproc~inverse~sunt~1,4~si~-\frac57 [/tex]
