Answer:
[tex]y = \frac{1}{4} x[/tex]
Step-by-step explanation:
1) First, find the slope of the equation. Use the slope formula [tex]m= \frac{y_2-y_1}{x_2-x_1}[/tex]. Substitute the x and y values of the given points into the formula and solve:
[tex]m = \frac{(2)-(1)}{(8)-(4)} \\m = \frac{2-1}{8-4}\\m = \frac{1}{4}[/tex]
Thus, the slope is [tex]\frac{1}{4}[/tex].
2) Now, use the point-slope formula [tex]y-y_1 = m (x-x_1)[/tex] to write the equation in point-slope form (from there we can convert it to slope-intercept). Substitute values for [tex]m[/tex], [tex]x_1[/tex], and [tex]y_1[/tex].
Since [tex]m[/tex] represents the slope, substitute [tex]\frac{1}{4}[/tex] for it. Since [tex]x_1[/tex] and [tex]y_1[/tex] represent the x and y values of one point the line intersects, choose any of the given points (it doesn't matter which one, the end result will be the same) and substitute its x and y values into the formula as well. (I chose (4,1), as seen below.) Then, isolate y to put the equation in slope-intercept form and find the answer.
[tex]y-(1) = \frac{1}{4} (x-4)\\y-1 = \frac{1}{4} x-1\\y = \frac{1}{4} x+0\\y=\frac{1}{4}x[/tex]