Name —————————————————————— Date ——————————— SPI 0806.3.7 Identify, compare and contrast functions as linear or nonlinear. The vertical line test is used to determine whether a relation represented by a graph is a function. A relation is a function provided that no vertical line passes through more than one point on the graph. Function Not a Function y y 1 22 O 2 O x 1 x 22 The graph of a linear function must pass the vertical line test and it must be a straight line with no bends. Linear Function Nonlinear Function y y 1 1 21 © Houghton Mifflin Harcourt Publishing Company 1 21 x Which statement about linear and nonlinear functions is always true? 2 A The graph of a nonlinear function B The graph of a linear function has a negative slope. C The graph of a nonlinear function is parallel to the x-axis. D The graph of a linear function is a line. Which equation represents a linear function? F has a positive slope. x 3x 5 y G y 5 x2 3 H y 5 2x3 J 2x4 5 y 1 5 Which equation represents a linear function? A x3 1 2 5 y B x y 1 __ 2 5 21 C y 5 2x2 D y 5 x4 1 3 GO ON Grade 8 Tennessee 8_MTNBETP478555_SPI_0806.3.7.indd 63 SPI 0806 63 8/28/10 4:51:31 PM Name —————————————————————— SPI 0806.3.7 4 (continued) Each of these graphs is the graph of a linear function, except which one? F 4 5 Which graph is the graph of a function? A y 2 0 -4 Date ——————————— x -2 2 4 -2 B -4 y G 2 0 -4 C x -2 2 4 -2 -4 4 y D 2 0 -4 x -2 2 4 -2 -4 6 J 4 y F 2 0 -4 -2 x 2 -2 -4 Which statement about functions and linear functions is true? The graph of a function may have an undefined slope. G The graph of a linear function may have an undefined slope. 4 H The graph of a linear function may be parallel to the x-axis. J The graph of a linear function may be parallel to the y-axis. © Houghton Mifflin Harcourt Publishing Company H GO ON 64 SPI 0806 8_MTNBETP478555_SPI_0806.3.7.indd 64 Grade 8 Tennessee 8/28/10 4:51:32 PM Name —————————————————————— SPI 0806.3.7 7 Date ——————————— (continued) Each table of values represents points on the graphs of four different lines. 9 Which graph is the graph of a linear function? A y x y x y 0 0 0 0 3 1 3 2 3 2 1 2 6 4 6 3 9 6 9 x y x y 0 0 0 5 3 3 3 7 6 6 6 9 9 9 9 11 4 24 23 22 21 0 21 22 23 1 2 3 4 x 1 2 3 4 x 1 2 3 4 x 1 2 3 4 x 24 B y 4 3 2 1 Which statement about the graphs of the lines is true? 24 23 22 21 0 21 22 23 A None of the lines represent linear functions. 24 B One line represents a linear function. C Three lines represent linear functions. C y 4 3 © Houghton Mifflin Harcourt Publishing Company D All of the lines represent linear 2 1 functions. 8 24 23 22 21 0 21 22 23 Which lines represent the graph of a function? 24 \ 4 3 D y 4 p 3 1 24 23 22 2 22 23 1 2 3 4 [ r q F lines q and r s H lines q, r, and s G lines s and p and s J 2 1 24 23 22 21 0 21 22 23 24 lines p, q, r, GO ON Grade 8 Tennessee 8_MTNBETP478555_SPI_0806.3.7.indd 65 SPI 0806 65 8/28/10 4:51:33 PM Name —————————————————————— SPI 0806.3.7 10 (continued) This chart shows the unit cost per item for quantities in multiples of 1,000. 11 In this graph of a linear function, what relationship appears to be shared by the n- and p-coordinates of points on the line? Quantity Unit Cost 1,000 $0.15 8 2,000 $0.14 3,000 $0.13 6 4 2 4,000 $0.12 5,000 $0.10 Is the relationship shared by the data an example of a linear function? Why or why not? F Date ——————————— No, because graphing the data requires axes that are not labeled x and y. p 28 26 24 22 22 2 4 6 8 n 24 26 28 A The value of p is 1 less than twice the value of n. B The value of n is 1 less than twice the value of p. not a straight line. C The value of p is one-half the value of n. H Yes, because any multiple of 1,000 can be purchased at a fixed unit cost. D The value of n is greater than the J Yes, because the data can be graphed. value of p. © Houghton Mifflin Harcourt Publishing Company G No, because the graph of the data is GO ON 66 SPI 0806 8_MTNBETP478555_SPI_0806.3.7.indd 66 Grade 8 Tennessee 8/28/10 4:51:34 PM