That is all the question says. we are working with slope intercept form and standard form and the lessons like that. I just dont get this

Use the slope formula: m = (y2 - y1)/(x2 - x1). In this case:

x1 = 4, y1 = a, x2 = 8, y2 = 3a

so plug in:

m = (3a - a)/(8 - 4) = 2a / 4

But since 2a/4 = 1/3, cross-multiply and solve the proportion. You get

6a = 4, so

a = 4/6 = 2/3