Which lines are perpendicular to 6x+18y=5

If the graphs of the linear equations in a system are parallel, what does that mean about the possible solution(s) of the system? a. there are infinitely many solutions. b. there is no solution. c. there is exactly one solution. d. the lines in a system cannot be parallel.

Which point lies on a circle with a radius of 5 units and center at p(6, 1)?

What is the image of c for a 90° counterclockwise rotation about a? (3, 7) (-1, 3) (7, 3)