2 3/5 math fractions ​

X+ y = 5 ; x - y =3 solve using linear combination

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?