$1.$ Write a set of Excel functions in cell Orders!G$2,$ which can be copied down the column to cell G$14,$ to determine the corresponding computer cost$$ based on the product number in the Inventory worksheet. $($Assume all clients will purchase the computer and the associated upgrades.$)$ If the product number does not exist in the inventory, display the word, $$INVALID$.($Hint: Use the IFERROR$($VLOOKUP$()+$ VLOOKUP$())$ functions here where the first VLOOKUP finds the base price and the second VLOOKUP finds the upgrades cost.$)$