# Pre-Algebra Examples

Find the Equation Using Point-Slope Formula
,
Step 1
Find the slope of the line between and using , which is the change of over the change of .
Step 1.1
Slope is equal to the change in over the change in , or rise over run.
Step 1.2
The change in is equal to the difference in x-coordinates (also called run), and the change in is equal to the difference in y-coordinates (also called rise).
Step 1.3
Substitute in the values of and into the equation to find the slope.
Step 1.4
Simplify.
Step 1.4.1
Simplify the numerator.
Step 1.4.1.1
Multiply by .
Step 1.4.1.2
Subtract from .
Step 1.4.2
Simplify the denominator.
Step 1.4.2.1
Multiply by .
Step 1.4.2.2
Step 1.4.3
Move the negative in front of the fraction.
Step 2
Use the slope and a given point to substitute for and in the point-slope form , which is derived from the slope equation .
Step 3
Simplify the equation and keep it in point-slope form.
Step 4
Solve for .
Step 4.1
Simplify .
Step 4.1.1
Step 4.1.2
Combine and .
Step 4.1.3
Move to the left of .
Step 4.2
Add to both sides of the equation.
Step 5
Reorder terms.
Step 6
Remove parentheses.
Step 7
List the equation in different forms.
Slope-intercept form:
Point-slope form:
Step 8