Consider the difference quotient formula.

Evaluate the function at .

Replace the variable with in the expression.

Simplify the result.

Apply the distributive property.

The final answer is .

Reorder and .

Find the components of the definition.

Plug in the components.

Simplify the numerator.

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Multiply by .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Apply the distributive property.

Multiply .

Multiply by .

Multiply by .

Multiply by .

Add and .

Add and .

Subtract from .

Add and .

Combine exponents.

Factor out negative.

Multiply by .

Divide by .

Find the Difference Quotient f(x)=-3x+9