We need to find the equation of a line that passes through the point \((-8, 10)\) and is parallel to the line given by \(5x + 4y = 13\). The equation should be in the form \(ax + by = c\), where \(a, b,\) and \(c\) are integers with no common factors, and \(a \geq 0\).
The given line is \(5x + 4y = 13\). To find the slope, we can rewrite this in slope-intercept form \(y = mx + b\).
\[
5x + 4y = 13 \implies 4y = -5x + 13 \implies y = -\frac{5}{4}x + \frac{13}{4}
\]
The slope \(m\) of the given line is \(-\frac{5}{4}\).
Since parallel lines have the same slope, the line we are looking for will also have a slope of \(-\frac{5}{4}\).
We use the point-slope form of the equation of a line, which is \(y - y_1 = m(x - x_1)\), where \((x_1, y_1)\) is the point \((-8, 10)\) and \(m = -\frac{5}{4}\).
\[
y - 10 = -\frac{5}{4}(x + 8)
\]
First, distribute the slope on the right-hand side:
\[
y - 10 = -\frac{5}{4}x - \frac{5}{4} \cdot 8
\]
\[
y - 10 = -\frac{5}{4}x - 10
\]
Next, add 10 to both sides to isolate \(y\):
\[
y = -\frac{5}{4}x
\]
We need to convert \(y = -\frac{5}{4}x\) to the form \(ax + by = c\). Multiply every term by 4 to clear the fraction:
\[
4y = -5x
\]
Rearrange to get the standard form:
\[
5x + 4y = 0
\]
The coefficients \(5\) and \(4\) have no common factors, and \(a = 5 \geq 0\).
\[
\boxed{5x + 4y = 0}
\]