Question

r/2+r/5+1=r/2+3
2r/3+r/5-r/3=r/2+r/3+9
y/4-2y/5+3/4=4y/5+y/4

Answer 1

R/2+r/5+1=r/2+3

r/2 + r/5 - r/2 = 2
(10r +4r - 10r)/ 20 = 40/20
10r+ 4r - 10r = 40
4r = 40
r= 10

2r/3+r/5-r/3=r/2+r/3+9
2r/3+r/5-r/3 - r/2 - r/3 = 9
(20r +6r - 10r - 15r - 10r )/30 = 270/30
26r - 35r = 270
-9r = 270
r = -30 

espero que tenha ajudado :)