How do i bond 6 x 9 by adding 48 + 6

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

Im literally having a mental breakdown

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