The quantities x and y are proportional. x = 4, 5, 10. y = 10, 12.5, 25. find the constant of proportionality (r) in the equation y = rx.

r = 2.5

Step-by-step explanation:

given the equation y = rx ← r is the constant of proportionality

then r =

from the given values of x and y

r = = = = 2.5

y = 3x+4

step-by-step explanation:

to find the slope

slope = (y2-y1)/ (x2-x1)

    = (-8-4)/ (-4-0)

    = -12/-4

  = 3

using the slope intercept form of a line

y= mx+b

we know the slope is 3

we know the y intercept is 4 ( the point where it crosses the y axis or x=0)

y = 3x+4

the answer is c. ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀