va rog,imi trebuie rezolvarea rapid

[tex](\frac{1}{40} -\frac{8}{15} ):z=-\frac{122}{60} \\(\frac{3}{120} -\frac{64}{120} )):z=-\frac{122}{60} \\\\-\frac{61}{120} :z=-\frac{122}{60} \\z=\frac{122}{60} *\frac{120}{61} \\z=\frac{4}{1} \\z=4[/tex]