Which angle number represents an angle adjacent to ∠PSL

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Could somebody me with this radical simplification?

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