Please help to solve the below questions with step-by-step explanation

Each of the walls of a room with square dimensions has been built with two pieces of sheetrock, a smaller one and a larger one. the length of all the smaller ones is the same and is stored in the variable small. similarly, the length of all the larger ones is the same and is stored in the variable large. write a single expression whose value is the total area of this room. do not use any method invocations.

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Me i’m stuck on all these questions besides the two bottom ones