" ..y varies directly with x" ---> y = kx
when y=15, x=5
15 = k(5)
k = 3
so y =3k
then when x = 9, y = 27
Suppose y varies directly with x, and y = 15 and x = 5. Write a direct variation equation that relates x and y. What is the value of y when x 9?
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