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Name ___________________ Date ___________ Algebra I Unit 10 Day 3 Direct and Inverse Variation Direct Variation _____________________, where k is the ___________ of variation or __________. Do the following equations represent direct variation? If so, identify the constant. 1 x 2 y = -2x + 3 y= 2x – 3y = 0 x+y=4 Graphing direct variation equations. Direct variation equations always go through the _____________________. y= 2 x 3 y = -x Write direct variation equations for the following. Y and x vary directly. Write a direct variation equation that relates x and y. Find the value of y when x = 14. x = 3, y = 6 x = -2, y = 18 x = 10, y = 5 x= 1 ,y=2 4 Bryan works a part-time job and his paycheck total varies directly with the number of hours that he works. Write a direct variation equation that relates Brian’s total paycheck and number of hours if he makes $111 for working 12 hours. How much will Bryan earn if he works 23 hours? How many hours does Bryan work if he makes $157.25 Inverse Variation __________, where k is the _______________ of variation. Tell whether x and y show direct variation, inverse variation or neither. Identify the constant. xy = 7 y x 4 y = -x + 3 x y x y 1 2 3 2 2 4 6 1 4 8 12 1 2 18 1 3 9 18 The variables x and y vary inversely. Use the given values to write an equation relating x and y. Then find y when x = 3. x = 5, y = -4 x = 1, y = 9 The number of hours, h, it takes for a block of ice to melt varies inversely as the temperature, t. Write an equation that relates number of hours with temperature if it takes 2 hours for a square inch of ice to melt at 65ºF. How long would it take for an inch of ice to melt at 100ºF?