# Precalculus Examples

,

Slope is equal to the change in over the change in , or rise over run.

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).

Substitute in the values of and into the equation to find the slope.

Simplify.

Simplify the numerator.

Multiply by .

Subtract from .

Simplify the denominator.

Multiply by .

Subtract from .

Move the negative in front of the fraction.

Use the slope and a given point to substitute for and in the point-slope form , which is derived from the slope equation .

Simplify the equation and keep it in point-slope form.

Simplify .

Apply the distributive property.

Combine and .

Multiply .

Multiply by .

Combine and .

Multiply by .

Move to the left of .

Move all terms not containing to the right side of the equation.

Add to both sides of the equation.

To write as a fraction with a common denominator, multiply by .

Combine and .

Combine the numerators over the common denominator.

Simplify the numerator.

Multiply by .

Add and .

Reorder terms.

Remove parentheses.

List the equation in different forms.

Slope-intercept form:

Point-slope form: