I'll do 3 and 4, and you can do 5 and 6 on your own!
For 3, we know that a perpendicular line's slope is -1/the other one, so the form is y=x/5+b (b being any number). Plugging -5 and -3 in, we get -3=-1+b. Adding 1 to both sides, we get -2=b and our equation being y=x/5-2 (since our standard form is y=mx+b with y and x remaining variables)
For 4, parallel means the same slope, so we have y=-2x/5+b. Plugging (2,4) in, we get 4=-4/5+b. Adding 4/5 to both sides, we get 4+4/5=b and our equation being y=-2x/5+4+4/5
