SECTION 4.2LINEAR RELATIONS
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REVIEW: X AND Y AXIS
X-axis (Horizontal) is known as the independent axis
Y-axis (Vertical) is known as the dependent axis
Each point on the grid has a coordinate in the form of (x,y)
x
y
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X-axis (Horizontal)
Y-axis(Vertical)
Origin(0,0)
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II) LINEAR RELATIONS
“Linear” means ‘straight line’
Two variables have a relationship if one variable canaffect the other
ie: your salary vs how many hours your work
How much you pay vs how much you buy
A relationship is linear if the two variables increase ordecrease at a constant ratio
Ie: each hour you work, your salary increases by $20
You pay another $25 for each additional hour of tutoring...
When you graph a linear relationship, you will get astraight line
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III) GRAPHING LINEAR RELATIONS
Make a TOV
Plot the points on the grid
Connect the DOTS!!
Ex: Given the equation, make a TOV and graph it
x
y
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When making a TOV,
pick nice numbers for “x”
Plot the points on the grid
Connect the DOTS
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Practice: Make a TOV and graph the linear function
x
y
0
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When making a TOV,
pick nice numbers for “x”
Plot the points on the grid
Connect the DOTS
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y
0
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IV) APPLICATIONS OF LINEAR RELATIONS
Sometimes when you graph a linear relation, you should notconnect the dots
This occurs when the “x” variable represents things that canonly be whole numbers
Ie: number of people, number of cookies you purchased
Ex: The cost for renting a banquet hall is given by the equationbelow. Draw a graph to illustrate the cost vs number of people
You can not have half a person coming or 1.5person. So don’t connectthe dots!!
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HOMEWORK:
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