1.   Choose the relation that is a function.
    A. B.
    C. D.
    Hint

  2.   Determine which equation represents a function.
    A. x = 4 B. x = y2 - 1
    C. D. y = -2x + 1
    Hint

  3.   In a science experiment, students hung a cup from a spring and measured the length of the spring when candies were added to it. Their data are shown in the table below. Which statement is true?
   
    A. The relation is a function because for each x value, there is exactly one y value.
    B. The relation is not a function because there are two y values for some x values.
    C. The relation is a function because the range values increase.
    D. The relation is not a function because only a line can be a function.
    Hint

  4.   Given the function f(x) = x2 + 9, find f(-3).
    A. 0 B. 12
    C. 6 D. 18
    Hint

  5.   The temperature f(x) of water in a lake in degrees Fahrenheit is estimated by the function shown below, where x is the depth in feet of the water. What would be the temperature of water 30 feet below the surface?
   
    A. 33°F B. 63°F
    C. 111°F D. 71.25°F
    Hint



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