Which two statements are correct about the average rate of change for the function f(x)=x2+9x+18

The depth of a lake at a certain point, wich is a function of the distance of that point from shore, is 30 feet.

Anyone know? will mark brainliest if you're correct!

Agroup of students want to create a garden. they do not know the exact measurements but they propose using a variable to represent the length and width of the garden. the length of the garden is 10 feet longer than double the width. use a single variable to write algebraic expressions for both the length and width of the garden. write an algebraic expression for the area of the garden. use mathematical terms to describe this expression.