# mathematics

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Draw a graph of the mirror line y=x, the function f:x 3x+2 and its inverse f`1 x x-2/3, for the domain of x, -2<x<8

x -2 0 4 8
y=x -2 0 4 8
These numbers were given to me what i want to know is why 0 and 4 and how do i come up with the numbers on my own for future questions??

• mathematics - ,

The choice of x vales to use depends very much on the question and what you are asked to show. It is quite usual to calculate the value for x=0. In this case where the function is a straight line you only really need to have values for x=-2 and x=8 and then draw the straight line between them.

Where the function is not a straight line then having several values helps to construct the line. It is usual to have both +ve and - values of x.

• mathematics - ,

The question requires you to graph the three functions. The x-values given are suggested values, as explained by Dr. Russ.

Plot the functions graphically and you will be able to make observations and remarks.
Here's my version of the graph:
http://i263.photobucket.com/albums/ii157/mathmate/trina.png