322 Review Questions and Answers
That means Δy/Δx= 2/5, which is the slope of the line. The y-intercept is the y-value at Q,
becauseQ happens to lie on the y axis. That value is −1.
Question 15-2
In Fig. 20-5, how can we determine the slope of line QR? The y-intercept?
Answer 15-2
We know the ordered pairs for the two points as Q= (0,−1) and R= (2,4). Therefore,
Δy= 4 − (−1)
= 4 + 1
= 5
and
Δx= 2 − 0
= 2
That means Δy/Δx= 5/2, which is the slope of the line. As with line PQ, the y-intercept is −1,
which is the y-value at point Q.
–6 246
2
4
6
–2
–4
–6
–4 –2
x
y
P
Q
R
Figure 20-5 Illustration for Questions and Answers
15-1 through 15-10.