Test 7 Section 3 #19

Because you’re told that (1, 4) and (2, 0) are on the line, you can easily calculate its slope!

\text{slope}=\dfrac{y_2-y_1}{x_2-x_1}=\dfrac{4-0}{1-2}=\dfrac{4}{-1}=-4

From there, just use the points you know and the slope to count steps back to the y-axis. It’s only one step! From (1, 4), a slope of –4 tells you that you go up 4 steps when you go left 1 step. That lands you on (0, 8). Therefore, b = 8.