For which values of A, B, and C will Ax + By = C be a vertical line through the point (7, 4)?

Me i'm timed right now! there's 4 answer

Step by step explanation pls for 10 pts the length of a rectangular board is 3 feet less than twice its width. a second rectangular board is such that each of its dimensions is the reciprocal of the corresponding dimensions of the first rectangular board. if the perimeter of the second board is one-fifth the perimeter of the first, what is the perimeter of the first rectangular board?  

What is the height of a cylinder with a volume of 384x cubic inches and a radius of 8 inches? round to the nearest tenth of an inch