Answer:
slope = 5
Step-by-step explanation:
The equation of a lin in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
y = 5x + 3 ← is in slope- intercept form
with slope m = 5
Parallel lines have equal slopes , then
The slope of a line parallel to y = 5x + 3 is 5
Check the picture below.
now, to get how much is the area of the tiled section, we simply get the area of the whole pool, 53x26, which includes the tiles, and then subtract the area without the tile, the rectangle in the middle, and what's leftover, is the area of the tiled area.

I don't think there is a way to answer your question.
All whole numbers are integers, so since 0 is a whole number, 0 is also an integer.
15+(10-x)=15 would be your equation if that is what you are looking for.