Direct and Inverse Variation
Explore direct and inverse variation relationships through equations, tables, and graphs for 8th-grade math students.
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Direct and Inverse Variation
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Date:
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Read each question carefully and answer to the best of your ability. Show all your work for full credit.
1. Which equation represents a direct variation?
y = 3x + 2
y = 5/x
y = -4x
y = x - 7
2. If y varies inversely with x, and y = 6 when x = 2, what is the constant of variation?
3
12
8
4
3. In a direct variation, as one quantity increases, the other quantity .
4. The graph of a direct variation is always a line that passes through the .
5. In an inverse variation, if x is doubled, y is .
6. The amount of flour needed for a recipe varies directly with the number of servings. If 2 cups of flour are needed for 8 servings, how many cups of flour are needed for 12 servings?
7. Plot the points for the direct variation equation y = 2x on the graph below.
8. The product of x and y is constant in a direct variation.
True
False
9. If y varies inversely with x, then as x increases, y decreases.
True
False
10. The time it takes to travel a certain distance varies inversely with the speed. If it takes 3 hours to travel a distance at 60 mph, how long will it take to travel the same distance at 45 mph?