Someone pls ! im confused (provide step by step process )

r= 3b

Step-by-step explanation:

We can find the slope of the line by using

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

   = (12-9)/ (4-3)

   = 3/1

The slope is 3

We can use the point slope form for the equation of a line

y-y1 = m(x-x1)

y-12 = 3(x-4)

Distribute the 3

y-12 = 3x-12

Add 12 to each side

y -12+12 = 3x-12+12

y= 3x

let r =y

and x=b

r = 3b

yes

step-by-step explanation: