the quantities x and y are proportional: 8, 1.6, 15, 3, 22, 4.4 use y+rx

Question

I'm a bit confused by the constants of proportionality even though it looks very simple and concrete.

 

Any explanation of this would be greatly appreciated.

 

Thank you so much. -7th grader

Answer 1

I think if you write your question in paired form, it's easier to understand: (8, 1.6) and (15, 3) etc.

 

I assume your full equation is y + rx = 0

 

if 15 = x and 3 = y, then y + rx = 0 would be 3 + r(15) = 0, so, r = -1/5