2nd: Noting general equation, y = mx + c m = slope, c = vertical intercept. From the graph, slope = (2,0) and (0, -4) = (-4 -0) / (0 - 2) = -4/-2 = 2. Vertical intercept, c = -4. y = mx + c , y = 2x + (-4), y = 2x - 4 = D.
3rd: f(x) = x^2 - x, f(-4). we would substitute x = -4.