Give reasons for your answer. y' = 8 − y = 0 on the lines x = 0 and y = 0, and y' > 0 for 0 < x < π/8, 0 < y < π/8. the slopes at each point are independent of y, so the slopes are the same along each line parallel to the y-axis. note that for y = 8, y' = 0. the slopes at each point are independent of x, so the slopes are the same along each line parallel to the x-axis. note that for y = 8, y' = 0. y' = 8 − y = 0 on the lines x = 0 and y = 8. y' = 8 − y = 0 on the line y = −x + 1/8, and y' = −1 on the line y = −x.