Explain how 18 is an even number

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.

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Is the square root of 4 plus the square root of 16 rational?