4. Writing Equations in Two Variables
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Make a function table to obtain ordered pairs.
To graph the function y= 23x+8, we will follow two steps.
To make a function table, we will select some values of x. 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 | 2/3x+8 | y | (x,y) |
---|---|---|---|
- 4 | 2/3( - 4)+8 | 16/3 | ( - 4, 16/3) |
0 | 2/3( 0)+8 | 8 | ( 0, 8) |
2 | 2/3( 2)+8 | 28/3 | ( 2, 28/3) |
4 | 2/3( 4)+8 | 32/3 | ( 4, 32/3) |
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= 23x+8.