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Slope • The slope of a line means the ratio of the vertical change to the horizontal change between two points on the graph of a line. 
i.e. slope=
Notice :
Not the value of y/x, but (change in y) / (change in x). • Especially, when change in x is 1 unit slope= =(change in y) Thus,
(for every 1 unit to the right)
Example
In Figure 1, the graph rises by 2 units for every 1-unit move to the right, 2 is the slope of the line. In Figure 2, the graph drops 3 units for every 1-unit move to the right, −3 is the slope of the line.  • In a straight line, the slope is a constant and you can use any two points to calculate the slope.In the right figure, the graph rises by 2 units for 1-unit to the right, by 4 units for 2-units to the right, by 6 units for 3-units to the right. Every ratio (change in y) / (change in x) is equal to 2.(i.e. the slope=2) |
Figure 1
In Figure 1, the graph rises by 2 units for every 1-unit move to the right, change of y is 2. slope= =2 Figure 2 
slope= =−3
Summary of slope
• Find two lattice points (points where two grid lines meet) on the line. Draw a right triangle like a stair step. From the first point to the second point, think of the vertical change and the horizontal change. slope= • Especially, change in y for every change in 1 unit to the right is equal to the slope. • When a line goes up left to right it has a positive slope. When a line goes down left to right it has a negative slope. |
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QuestionFind the slope of the graph described below. (Select the correct answer from the right column.) 
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 , Incorrect →  |