To determine the equation of a line depicted in a graph, you typically follow these steps:
- Identify Two Points on the Line: Look for two clear points that the line passes through. The coordinates of these points are typically in the format
(x_1, y_1)
and(x_2, y_2)
. - Calculate the Slope (m): The slope of the line is calculated using the formula:
m = (y_2 - y_1) / (x_2 - x_1)
. This gives you the steepness of the line. - Use the Point-Slope Form of the Equation: Once you have the slope, you can use one of the points to formulate the equation. The point-slope form is given by:
y - y_1 = m(x - x_1)
. - Rearranging to Slope-Intercept Form: If desired, you can rearrange the equation to the slope-intercept form,
y = mx + b
, whereb
is the y-intercept. To findb
, substitute one of your points back into the equation after findingm
.
For example, if you identify the points (1, 2) and (3, 4), you would calculate the slope:
m = (4 - 2) / (3 - 1) = 2 / 2 = 1
Then, using the point (1, 2):
y - 2 = 1(x - 1)
You can simplify this to find:
y - 2 = x - 1
y = x + 1
Thus, the equation of the line would be y = x + 1
.
By following these steps, you’ll be able to accurately find the equation of the line shown in the graph you are analyzing.