The problem asks us to factor the expression $16b + 5a - 20 - 4ba$.

1. Problem Description

The problem asks us to factor the expression $16b + 5a - 20 - 4ba$.

2. Solution Steps

We can rearrange the terms to group terms with common factors:

$16b + 5a - 20 - 4ba = 16b - 4ba + 5a - 20$

Now, we can factor by grouping. From the first two terms, we can factor out $4b$:

$4b(4 - a) + 5a - 20$

From the last two terms, we can factor out $5$:

$4b(4 - a) + 5(a - 4)$

We notice that $(a - 4)$ is the negative of $(4 - a)$, so we can rewrite it as $-(4 - a)$:

$4b(4 - a) - 5(4 - a)$

Now we can factor out the common factor $(4 - a)$:

$(4b - 5)(4 - a)$

3. Final Answer

$(4b - 5)(4 - a)$