2. Representations of Functions
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Make a function table to obtain ordered pairs.
To graph the function y=- 2x, we will follow two steps.
To make a function table, we will select some values of x which will be part of our domain. Then, we will substitute these values for x to find the corresponding values of y. These x- and y-values will create a set of ordered pairs.
x | -2x | y | (x,y) |
---|---|---|---|
0 | - 2( 0) | 0 | ( 0, 0) |
- 1 | - 2( - 1) | 2 | ( - 1, 2) |
- 2 | - 2( - 2) | 4 | ( - 2, 4) |
- 3 | - 2( - 3) | 6 | ( - 3, 6) |
We found four ordered pairs that lie on the graph of our function.
Next, we will graph the ordered pairs and connect them with a straight line.
The line is the complete graph of the function. The ordered pairs corresponding to any points on the line are solutions of the equation y=- 2x.