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**Unformatted text preview: **), Q(2, 4) 4. P (−3, 2), Q(4, 2) 2. P (−1, 2), Q(3, 4) 5. P (2, 3), Q(2, −1) 3. P (−2, 3), Q(2, −3) 6. P (2, 3), Q(2.1, −1) Solution. In each of these examples, we apply the slope formula, Equation 2.1.
y
4
Q
3 1. m= 4−0
4
= =2
2−0
2 2
1 P1 2 3 x 4 y
4
Q 2. 4−2
2
1
m=
==
3 − (−1)
4
2 3
2
P
1 −1 3 2 x 1 1 2 y
4
P 3
2 3. −3 − 3
−6
3
m=
=
=−
2 − (−2)
4
2 1 −3 −2 −1 3 x −1
−2
Q −3
−4 y
3 4. m= 2−2
0
= =0
4 − (−3)
7 2
Q P
1 −4 −3 −2 −1 1 2 3 4 x 2.1 Linear Functions 113
y
3 P 2
1 5. −1 − 3
−4
m=
=
, which is undeﬁned
2−2
0 1 x 2 −1 Q −2
−3 y
3 P 2
1 6. −1 − 3
−4
m=
=
= −40
2.1 − 2
0.1 1
−1 x 2
Q −2
−3 A few comments about Example 2.1.1 are in order. First, for reasons which will be made clear
soon, if the slope is positive then the resulting line is said to be increasing. If it is negative, we
say the line is decreasing. A slope of 0 results in a horizontal line which we say is constant, and
an undeﬁned slope results in a vertical line.2 Second, the larger the slope is in absolute value, the
steeper the line. You may recall from Intermediate Algebra t...

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