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Home > AC > Chapter 12 > Lesson 12.4.3 > Problem 12-90


The graphs of several relations are shown below. Decide if each is a function. If the relation is not a function, explain why not.

  1. This graph has 3 sections. The left section is a ray starting at the point (negative 2, comma negative 1) and going left and up. The center section starts at the point (negative 2 comma negative 1) and goes to the point (1, comma 4). The right section starts at the point (1, comma 4) and goes horizontally to the right.

    A relation is only a function if there is only one -value for each -value. Are there any -values on this graph that have multiple -values?

    This relation is a function.

  1. This graph is a circle center at the point (1, comma 1) with a radius of 3.

    See the help for part (a).

    This relation is not a function. Be sure to explain why.

  1. This graph is a scatterplot with the following points: (negative 4, comma 0), (negative 3, comma 2), (negative 1, comma negative 1), (negative 1, comma negative 3), (0, comma 1), (1, comma 2), (2, comma 1), (3, comma negative 4), (4, comma negative 2).

    See the help for part (a).