Answer:

Explanation:
The slope-intercept form of an equation of a line:

m - slope
b = y-intercpt → (0, b)
The formula of a slope:

We have the points (4, 2) and (0, -1) - y-intercept → b = -1.
(we see this already which equation. Only in b) y-intercept is b = -1).
Anyway, calculate the slope:

Finally we have the equation:
