Is this a direct variation? Course 2 Identifying DV xy -2-4 -2 00 12 24 xy 00 16 212 318 424 xy 36...
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Is this a direct variation? Course 2 Identifying DV x y -2 -4 -1 -2 0 0 1 2 2 4 x y 0 0 1 6 2 12 3 18 4 24 x y 3 6 5 10 7 14 4 8 6 12
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Transcript of Is this a direct variation? Course 2 Identifying DV xy -2-4 -2 00 12 24 xy 00 16 212 318 424 xy 36...
Is this a direct variation?
Course 2
Identifying DV
x y
-2 -4
-1 -2
0 0
1 2
2 4
x y
0 0
1 6
2 12
3 18
4 24
x y
3 6
5 10
7 14
4 8
6 12
Is this a direct variation?
Course 2
Identifying DV
2 8x y
8y x
2y
x
4y
x
1
8
y
x
y x
5x
y
1 3 1y x
2 0x y
Insert Lesson Title Here
Course 2
DV Problems
QUESTIONHow are direct
variation problems solved using the
equation?
Course 2
DV Problems
To solve problems:1. If there is more than one set of
data, make a t-table with the given information.
2. Using the equation y = kx or the ratio k = y/x, substitute the known values.
3. Solve for k.
Course 2
DV Problems
4. Substitute the k value into direct variation equation.
5. Solve for the value of y.
Find an equation of direct variation.
y is -12.5 when x is 4
Course 2
DV ProblemsExample:
Example:
Insert Lesson Title Here
Course 2
DV Problems
x varies directly with y. If y = 8 when x = 12, what is the value of
y when x = 15?
x y
12 8
15 ?
Insert Lesson Title Here
Course 2
DV Problems
QUESTIONHow are direct
variation problems solved using proportion?
Course 2
DV Problems
1. Substitute given values into the proportion
2. Solve for the value of y using cross product.
1 2
1 2
x x
y y
x varies directly with y. If y = -12.5 when x = -2.5, what is the value of y when x = -8?
Course 2
DV ProblemsExample:
2
2.5 8
12.5 y
Insert Lesson Title Here
Course 2
DV Problems
1. Find an equation of the direct variation when y is -64, x is 4.
2.Find an equation of the direct variation when y is 6.3, x is 0.7
3.Find an equation of the direct variation when y is ½ , x is ¼ .
Practice Problems
y = -16x
y = 9x
y = 2x
6416
44k
6.39
0.7k
1 12
2 4k
Insert Lesson Title Here
Course 2
DV Problems
1. x varies directly with y. If x = 5 when y = 4.45, what is the value of y when
x = 7.12?
2. x varies directly with y. If x = -2 when y = -3/2, what is the value of y when
x = -4?
3. x varies directly with y. If x = 5 when y = 4.5, what is the value of y when x = 1.5?
Practice Problems
y = 6.3368
y = -3
y = 1.35
Is this a direct variation?
Course 2
Identifying DV
x y
-2 -4
-1 -2
0 0
1 2
2 4
x y
0 0
1 6
2 12
3 18
4 24
x y
3 6
5 10
7 14
4 8
6 12
Is this a direct variation?
Course 2
Identifying DV
2 8x y
8y x
2y
x
4y
x
1
8
y
x
y x
5x
y
1 3 1y x
2 0x y
