Answer
Required sales are $x=4480$.
Work Step by Step
It is logical do demand that all of the $x$ produced units are sold so the sale also equals $x$. To find the required $x$ we have to equate $R=C$:
$$2.04x+5600 = 3.29x.$$
We can collect all the terms containing $x$ on one side:
$$3.29x-2.04x=5600\Rightarrow 1.25x=5600$$
so the sales required are
$$x=\frac{5600}{1.25} = 4480.$$
