Need Help really difficult

Ten times the square of a non-zero number is eqaul to ninety times the number

Which value of m will create a system of parallel lines with no solution? y= mx - 6 8x - 4y = 12

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?