What is 820.681 in expanded form, using powers of 10?

The graph of f(x), shown below, resembles the graph of g(x) = x2, but it has been changed somewhat. which of the following could be the equation of f(x)?

Can someone me do math because i am having a breakdown rn because i don’t get it

Write an algebraic expression to match each statement a. four less than 8 times a number b. twice the difference of a number and six c. nine from a number squared