What is the constant of proportionality of

1. y=2.0+ 0.5x

2.y=75x
3.y=55x

4.y=320-15x

5. y= 15/60 x+30

6.y=2.25
7.y=5x+3

8.y=3-0.6x
9.y=15+ 1/2x
10.y=65x


Thank you, no fake answers please!

Comment any questions.

These are all my points .-. please do at least 5.