8.1 Review Worksheet, Part 1
8.1.1 Variation Functions Given: y varies directly as x . Write and graph each direct variation function. 1. y = 4 when x = 8 2. y = 12 when x = 2
3. y = − 15 when x = 5
4. The dosage d of a drug that a physician prescribes varies directly as the patient’s mass m , and d = 100 mg when m = 55 kg. Find d to the nearest milligram when m = 70 kg.
5. The number of Calories C in a horned melon varies directly as its weight w , and C = 25 Cal when w = 3.5 oz. How many Calories are in the horned melon shown on the scale? Round to the nearest Calorie.
12.35 oz
6. The number of bags of soybean seeds N that a farmer needs varies jointly as the number of acres a to be planted and the pounds of seed needed per acre p , and N = 980 when a = 700 acres and p = 70 lb/acre. Find N when a = 1000 acres and p = 75 lb/acre.
7. The heat Q required to raise the temperature of water varies jointly as the mass m of the water and the amount of temperature change T , and Q = 20,930 joules (J) when m = 1 kg and T = 5°C. Find m when Q = 8372 J and T = 10°C.
Given: y varies inversely as x . Write and graph the inverse variation function. 8. y = 1 when x = 0.8 9. y = 1.75 when x = 6
10. y = − 2 when x = 3
197
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