Is 2x-5y-3 perpendicular to 5x 2y6?

If the slopes of the lines are negative reciprocals, then the lines are perpendicular.

2x - 5y = -3 subtract 2x to both sides

-5y = -2x - 3 divide both sides by -5

y = (2/5)x +3/5

5x + 2y = 6 subtract 5x to both sides

2y = -5x + 6 divide both sides by 2

y = (-5/2)x + 3

Yes, the lines are perpendicular.