9.
2x-5<3x
-5<x
=> A. (-5, infinit)
10.
2x=49-11
2x=38
x=38:2
x=19 => C.
11.
x/y=1/5
x+y= 90
x+y/y= 1+5/5
90/y=6/5
y=90x5/6
y=450/6
y=75
=> x= 90-75
x=15 => D.
bafta!
