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12-5 Direct Variation Warm-up Problems. Graph f(x) = x ² + x – 2. Chapter 12. 12-5 Direct Variation. Direct Variation. An equation of the form y = kx, where k is a nonzero constant, expresses direct variation . k is called the constant of variation. Example 1.
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12-5 Direct VariationWarm-up Problems • Graph f(x) = x² + x – 2.
Chapter 12 12-5 Direct Variation
Direct Variation An equation of the form y = kx, where k is a nonzero constant, expresses direct variation. k is called the constant of variation.
Example 1 • Find an equation of variation where y varies directly as x, and y = 2 when x = 1.
Try This • Find an equation of variation where y varies directly as x. One pair of values is given. a. y = 84 when x = 12 b. y = 50 when x = 80
Example 2 • The weight (V) of an object on Venus varies directly as its weight on (E) Earth. A person weighing 120 lb on Earth would weigh 106 lb on Venus. How much would a person weighing 150 lb on Earth weigh on Venus?
Try This c. The cost (c) of operating a TV varies directly as the number (n) of hours it is in operation. It costs $14.00 to operate a standard size color TV continuously for 30 days. At this rate, about how much would it cost to operate the TV for 1 day? 1 hour?