Question

3x-2y=13 2x+3y=-16 are these lines parallell or perpendicular or neither

Answer 1

3x - 2y = 13
-2y = -3x + 13
y = 3/2x - 13/2...slope is 3/2, y int is -13/2

2x + 3y = -16
3y = -2x - 16
y = -2/3x - 16/3...slope = -2/3, y int is -16/3

perpendicular lines will have negative reciprocal slopes. To find the negative reciprocal of a number, flip the number and change the sign.
On the 1st equation, the slope was 3/2....find its negative reciprocal.....flip it, making it 2/3....change the sign...making it -2/3. So the negative reciprocal of 3/2 is -2/3. 

So if one equation has a slope of 3/2 and another equation has a slope of -2/3, then these lines are perpendicular <==