What must you do when using a variable before prior to writing and running your code

Write pseudocode to represent the logic of a program that allows the user to enter a value. the program multiplies the value by 10 and outputs the result.

Use a software program or a graphing utility with matrix capabilities to solve the system of linear equations using an inverse matrix. x1 + 2x2 − x3 + 3x4 − x5 = 6 x1 − 3x2 + x3 + 2x4 − x5 = −6 2x1 + x2 + x3 − 3x4 + x5 = 3 x1 − x2 + 2x3 + x4 − x5 = −3 2x1 + x2 − x3 + 2x4 + x5 = 5

Someone plzz me which of these defines a social search? a. asking a search engine a question that is answered by a real person on the other sideb. modifying search results based on popularity of a web pagec. modifying search results based on a ranking of a web page