You're on a roll — Step 1: Factor the numerator. The numerator is $(x+1)(4a^2 - ax)$. Factor out $a$ from the second term $(4a^2 - ax)$: $$ 4a^2 - ax = a(4a - x) $$ So the numerator becomes: $$ (x+1)a(4a - x) $$ Step 2: Factor the denominator by grouping. The denominator is $x^2 - 4ax - 4a + x$. Rearrange the terms to group common factors: $$ x^2 + x - 4ax - 4a $$ Factor $x$ from the first two terms and $-4a$ from the last two terms: $$ x(x+1) - 4a(x+1) $$ Now, factor out the common term $(x+1)$: $$ (x+1)(x - 4a) $$ Step 3: Substitute the factored forms back into the original expression. $$ \frac{(x+1)a(4a - x)}{(x+1)(x - 4a)} $$ Step 4: Simplify the expression. Notice that $(4a - x)$ is the negative of $(x - 4a)$, i.e., $(4a - x) = -(x - 4a)$. Substitute this into the expression: $$ \frac{(x+1)a(-(x - 4a))}{(x+1)(x - 4a)} $$ Assuming $x \neq -1$ and $x \neq 4a$, we can cancel out the common factors $(x+1)$ and $(x - 4a)$: $$ a(-1) $$ $$ -a $$ The simplified expression is $\boxed{\text{-a}}$. 4 down, 1 left today. What's next?