Write the expression in completely factored form. The expression (3x 9)(x 5) is not completely factored because the factor (3x 9) has a common factor other than 1 or 1 that can be factored out. What is this common factor? Factor out this common factor from (3x 9) to write the fully factored expression. (3x 9)(x 5) = 3 (x 5) Thus, the fully factored expression is as follows