5.2DirectVariation.notebook
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1/5:WarmUp
Findthemissingcoordinategiventhatthelinebetweenthetwo
pointshasthegivenslope.
(x,4)and(1,2);m=
5.2DirectVariation.notebook
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January05,2016
Direction Variation:
When the ratio of two variables is
constant.
Ex 1).
Does the equation represent direction variation? If so, find the
constant of variation.
a) 4y = 5x b) 2x + 3y = 6
5.2:
Direct Variation
Date:
1/5
5.2DirectVariation.notebook
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January05,2016
Ex 2).
Write a direct variation equation.
a) Suppose y varies directly with x and y = 40 when x = 8 . What direction
variation equation relates x and y ? What is the value of y when x = 12 ?
b) Suppose y varies directly with x and y = 10 when x = 2 . What direct
variation equation relates x and y ? What is the value of y when x = 15 ?
c) Suppose n varies directly with p and n = 9 when p = 5 . What direct
variation equation relates n and p ? What is the value of n when p = 8 ?
d) Suppose v varies directly with k and v = 6 when k = 14 . What direct
variation equation relates v and k ? What is the value of k when v = 8 ?
5.2DirectVariation.notebook
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January05,2016
Ex 3). Graph a direction variation equation.
Suppose $15 (US) is worth about $150 Mexican pesos.
a) What is the equation that relates US dollars x to Mexican pesos y ?
b) What is the graph of the equation in part (a)?
5.2DirectVariation.notebook
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January05,2016
What do all direct variation equations have in common?
5.2DirectVariation.notebook
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January05,2016
Ex 4). Writing a direct variation from a table.
For the data in the tables, does y vary directly with x ? If it does, write
an equation for the direct variation.
a)b)
x
y
2
5
6
15
10
25
y
7
10
13
5.2DirectVariation.notebook
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Homework:
pg. 304 #1 – 7, 10 – 32 (e)