the slope of a line objective: to find the slope of a line and to graph a line given its slope and a...
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The Slope Of A LineObjective: To find the slope of a line and to
graph a line given its slope and a point.
What is slope?• There are several definitions,
but they are all related.
• Rate of change
21
21
xx
yyRun
Rise
Example
y
x
Distancein miles
TimeIn hours
(x1,y1)
(x2,y2)
run = x1 – x2
rise = y1 – y2
m = rise/run = (y1 – y2)/(x1 – x2) = miles/hour
Find the slope between the two points
• (2, 4) and (5, 1)• (-3, 1) and (6, 4)• (2, 3) and (-1, 3)• (-2, 5) and (-2, 7)
• m = -1• m = 1/3• m = 0• No slope or undefined
slope
Theorem• The slope of a line in standard form
Ax + By = C is -A/B
Point Slope Form• y – y1 = m(x – x1)
• Variation: y = y1 + (x – x1)m
Graph The Line Passing Through (1,2) with a slope m = ¼
• Start by graphing the point (1,2)
• Since slope is rise over run move up 1 unit and right 4 units
-4 -3 -2 -1
4321
1 2 3 4 5 6-1-2-3-4
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