13.8: Variations
Name: _______________________________________________
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Write an equation to describe the variation. Use k for the
Direct Variation
constant of proportionality.
Write a direct variation equation, y = kx, that satisfies the
4) b varies directly as x
ordered pairs in the table.
1)
x 0 4 14
y 0 2
7
MATH 200.P01/P03
Solve.
2)
x -4
y 20
5) y varies directly as x. If y = 210 when x = 14,
find y when x = 11.
0 4
6
0 -20 -30
Inverse Variation
Write an inverse variation equation, y =
Write a direct variation equation, y = kx, that describes the
graph.
3)
the ordered pairs in the table.
6)
9
x 1 -9
-2
2
9
2
y
9
-1
2
-
-5
x
2
-9
9
2
-4
-10
y
9
-2
4
-
y
10
5
(0, 0)
-10
-5
(4, 1)
5
10
x
7)
9
2
k
, that satisfies
x
Write an equation to describe the variation. Use k for the
constant of proportionality.
8) r varies inversely as w
Solve.
Solve.
12) y varies directly as x2. If y = 320 when x = 8,
find y when x = 9.
9) x varies inversely as v. If x = 12 when v = 4,
find x when v = 24.
13) x varies inversely as y2. If x = 2 when y = 20,
find x when y = 4.
Write an equation to describe the variation. Use k for the
constant of proportionality.
10) b varies directly as y5
11) z varies inversely as x 3
13.8: Variations
2
Answer Key
Testname: 13_8_VARIATIONS
1) y =
1
x
2
2) y = -5x
1
3) y = x
4
4) b = kx
5) y = 165
9
6) y =
x
7) y =
18
x
8) r =
k
w
9) x = 2
10) b = ky5
k
11) z =
x3
12) y = 405
13) x = 50
13.8: Variations
3