Dear mathlover14,

----------(1)

---------(2)

(1)+(2);

-------(This is a quadratic equation. So find the two answers for m+n)

(1)-(2);

--------(Find the two answers for m-n)

So ultimately you will have four equations (two values for m+n and two values for m-n). Using these four equations in different combinations you will be able to get 4 different answer sets. Hope you can continue.