After a 40% discount, the cost of a sofa is $471.00. What was the original cost of the sofa? NEED HELP ASAP

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.

Define multiplicative inverse. give an example of a number and its multiplicative inverse.

Could somebody me with this radical simplification?