Graphs of a functions

Question

Draw graphs of the following functions using axes from x=-3 to x=+3 and y

=20 to y=+20

 

1. y=4x+3

 

2. y= 2x+1

 

 

Please just a hint on this because I am a bit confuse with the y axis stuff.

Answer 1

These equations are equations of two lines.  Two points determine a line. 

 

Line 1.   y = 4x + 3

     has points   (-3,-9) and (3,15)   [connect the "*"with a line]

                       20 +

                             |

                       15 +                *

                             |

                       10 +

                             |

                         5 +

                             |

         - + - + - + - + - + - + - + -

           -3   -2   -1  |     1   2    3

                       -5  +

                             |

            *        -10 +

                             |

                      -15 +

                             |

                      -20 +

 

Line 2:    y= 2x+1

        has points    (-3,-5) and (3,7)       [connect the "*" to form this line]

                       20 +
                             |
                       15 +
                             |
                       10 +
                             |               *
                         5 +
                            |
        - + - + - + - + - + - + - + -
         -3   -2  -1    |    1    2    3
          *           -5 +
                            |
                     -10 +
                            |
                     -15 +
                            |
                     -20 +

Answer 2

Benny, you are going to draw your two lines, but only between -3 and 3 on the x-axis and -20 and 20 on the y-axis.

 

In other words, you can make a rectangle with 4 points, (-3,-20),(-3,20),(3,-20) and (3,20). You two lines should be inside this rectangle up to the sides.