How do i turn this equation from standard form to slope intercept form?

Which statements are true? see picture

Jack lives on a farm and has a large backyard. the area of his rectangular backyard is of a square mile. if the width of the yard is of a mile, what fraction of a mile is the length of the rectangular backyard?

1.based of the diagrams what is the the value of x? 2.how would you verify your answer for x