To be perpendicular the product of the two slopes must equal -1.
2m/5=-1
2m=-5
m=-2.5
since y=mx+b we have so far
y=-2.5x+b, using point (-3,4) we can solve for b
4=-2.5(-3)+b
4=7.5+b
b=-3.5 so
y=-2.5x-3.5 We can multiply the whole equation by two so that the coefficients are integers...
2y=-5x-7 add 5x to both sides
5x-2y=-7