Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
3. Linear Functions and Slope-Intercept Form
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Exercise 57 Page 79

Practice makes perfect
a Let's start by reviewing how to find the slope of a line. The slope is the ratio of the vertical change to the horizontal change between the points ( x_1, y_1) and ( x_2, y_2).
Slope &=& &Vertical change (rise)/Horizontal change (run) &=& &y_2-y_1/x_2-x_1

We can use the graph to find the coordinates of the points P and Q.

We can now find the slope using these points and the Slope Formula.
m = y_2-y_1/x_2-x_1
m = -2-( -5)/0-( -3)
m = -2+5/0+3
m = 3/3
m = 1
We found that the slope between P and Q is m=1.
b We will proceed just as we did in Part A.
We will use the given graph to find the coordinates of the points Q and S.
Now, we can find the slope by using the Slope Formula.
m = y_2-y_1/x_2-x_1
m = 2-( -2)/4- 0
m = 2+2/4 -0
m = 4/4
m = 1
We found that the slope between Q and S is m=1.
c Once more, we will use the given graph to find the coordinates of the points S and P.
Now, we can find the slope by using the Slope Formula.
m = y_2-y_1/x_2-x_1
m = -5- 2/-3- 4
m = -7/-7
m = 1
The slope between P and S is m=1.
d Finally, we will use the given graph to find the coordinates of the points R and Q.
Now, we can find the slope by using the Slope Formula.
m = y_2-y_1/x_2-x_1
m = -2-( -1)/0-( 1)
m = -2+1/0-1
m = -1/-1
m = 1
The slope between R and Q is m=1.
e As we can see from the previous parts of this exercise, the slope between all the pair of points given was the same, m=1. Notice that all these points lie on the same line. We can conclude that the slope between any pair of collinear points is the same.