If n=(81!  − 80!  + 79!)/(79!), which of the following could be subtracted from n so that √n is an integer?
Pick
A) 1	B) 2	C) 3	D) 4	E) 5
first lets find n.   n=(81! −80! +79!)/(79!)   n=81! /79!−80!/79! +79!/79!   n=81∗80−80+1=80(81−1)+1=80^2+1   so what should be subtracted from80^2+1, so that it becomes a perfect square ..   ans is 1, as 80^2−1+1=80^2   1NSWER:1
<result>A</result>
If n=(81!  − 80!  + 79!)/(79!), which of the following could be subtracted from n so that √n is an integer?