Respuesta :

mathstudent55

Answer:

-1/20

Step-by-step explanation:

r/2 + s/r - r/4 + 1/5 =

= -1/2 + 0/(-1) - (-1)/4 + 1/5

= -1/2 + 1/4 + 1/5

= -10/20 + 5/20 + 4/20

= -5/20 + 4/20

= -1/20