How would you search the data from another excel file without using the "vlookup" function?
"Index-match" function can be used instead of "vlookup". It can search the whole spreadsheet not only from left to right (as vlookup does).
How would you describe the pure monopol?
Pure monopoly properties: 1) there is only one buyer or seller on the market; 2) monopolist has no preference (non-discriminatory monopoly); 3) the market is fully accessible; 4) there is no competition.
What is Laffer curve?
That curve shows the relationship between the tax rates and the amount of tax revenue gathered by the government. It says, that starting from a some point the higher tax rates leads to the lower tax revenue.