Apples cost $2.19 a pound. in a relation, the input is the number of pounds of apples and the output is the cost. is this relation a function? why or why not?

This is different from the first one can someone me

What happens to the area as the sliders are adjusted? what do you think the formula for the area of a triangle is divided by 2?

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle.he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field