What is the slope of a line that is parallel to y 5x 3?

It has the same slope as the line in the question.

If a line has equation y = mx + c, its slope is m.

If the line in question is y = 5x + 3, the slope of a parallel line is 5;

If the line in question is y + 5x = 3 → y = -5x + 3 (subtract 5x from both sides), the slope of a parallel line is -5.