Hi can I get help on this I don’t understand it.

Acollege is planning to construct a rectangular parking lot on land bordered on one side by a highway. the plan is to use 680 feet of fencing to fence off the other three sides. what dimensions should the lot have if the enclosed area is to be a maximum?

Aportion of a line bounded by two points is defined as

For the equations below which statement is true ? -2x=14 6x=-42