Lisa apparently failed to realize that both terms inside the first set of parentheses have 3x as a factor. They are like terms, so could be combined directly. If Lisa really wants to factor out 3 or 3x, she could do so and then combine the remaining factors at another step.
Answer: Thus, the equation of a function stretched vertically by a factor of 2 and then shifted 3 units up is y = 2f (x) + 6, and the equation of a function stretched horizontally by a factor of 2 and then shifted 6 units left is y = f ( (x - 6)) = f ( x - ). Example: f (x) = 2x2.