2 49 - n -------------- 2 n - 14*n + 49
(49.0 - n^2)/(49.0 + n^2 - 14.0*n)
2 49 - n ---------------- 49 + n*(-14 + n)
-(7 + n) --------- -7 + n
14 -1 - ------ -7 + n