Graphs

Writing a Linear Equation to Describe a Table

You can use the data in a table to create a linear equation. You can use the data to find the slope. Once you know the slope, you can use one ordered pair and the point-slope form to create your equation.

Rules for Writing a Linear Equation from a Table

1. Choose two sets of ordered pairs. Find the slope.
2. Use one of the ordered pairs as the x and y coordinates in the point-slope form of an equation.
3. Place the values into the point-slope form.

Write a function to describe:

x	0	1	2	3
f(x)	0	2	4	6

1. Choose two sets of ordered pairs. Find the slope:

$m=\frac{y_2-y_1}{x_2-x_1}=\frac{2-0}{1-0}=2$

2. Use one of the ordered pairs as the x and y coordinates in the point-slope form of an equation.
3. Place the values into the point-slope form.

y-y₁=m(x-x₁)

y-0=2(x-0)

y=2x