The slope-intercept form is , where is the slope and is the y-intercept.

Subtract from both sides of the equation.

Divide each term by and simplify.

Divide each term in by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Simplify .

Simplify each term.

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Move the negative in front of the fraction.

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Reorder and .

Rewrite in slope-intercept form.

Using the slope-intercept form, the slope is .

The equation of a perpendicular line to must have a slope that is the negative reciprocal of the original slope.

Multiply the numerator by the reciprocal of the denominator.

Multiply by .

Multiply by .

Find the Slope of a Perpendicular Line 3x-9y=15