Step-by-step explanation:
For the two lines to be perpendicular one must it's gradient to be the negative reciprocal of the other;
3x + 5y = 10
5y = 10 - 3x
y = 2 - 3/5x
gradient = -3/5
5x - 3y = -6
5x + 6 = 3y
5/3x + 2 = y
gradient = 5/3
since the second line has the negative reciprocal of the first line, hence they are perpendicular.
