Answer
$$-(x-1)(16x+5) .$$
Work Step by Step
First, for the polynomial $5 + 11x - 16x^2$, we write
$$5 + 11x - 16x^2=-(16x^2-11x-5)=-(16x^2-16x+5x-5) .$$
By grouping the first two terms and the second two terms and then taking common factors, we have
$$-(16x^2-16x+5x-5)=-(16x(x-1)+5(x-1))\\
=-(x-1)(16x+5) .$$
