Question 456310
The confusing part is using x and y for those variables.
Usually they would be m and b

r=dy+x

90=100y+x
110=150y+x

x=50
y=2/5
the equation would be
r=(2/5)*d+50
check
90=2/5*100+50
90=40+50
ok
check
110=150*2/5+50
110=60+50
ok