Answer: y = 4x
Step-by-step explanation: Slope intercept form is y = mx + b where m is the slop and b is the x intercept
We can solve for slope using the given points
(2-1)/(8-4) = 1/4, thus m = 1/4
y = 1/4x +b
Now to solve for b, we can just plug in one of the points to see what makes b work
1 = 4*(1/4) + b
1 = 1 +b
b = 0