Chapter 13, Lesson 9


13-9.A understand the direction of a graph
For which coordinates will points P and Q determine a line that is falling?
I
P(—5, 0) and Q(0, 5)
II P(—3, 5) and Q(3, 5)
III P(0, 5) and Q(5, 0)
(a) I only (b) II only (c) III only (d) I and III only

13-9.B identify possible values for the slope of a line
Which statement is true about the slope of a line?
I
When a line and the positive portion of the x-axis form an acute angle, that line has a positive slope.
II When a line and the positive portion of the x-axis form an obtuse angle, that line has a negative slope.
III A horizontal line has a slope of 0.
(a) I, II, and III only (b) I and II only (c) I and III only (d) II and III only