n^2=18n + 40 n^2 - 18n - 40=0 n^2 -20n + 2n - 40=0 n(n - 20) + 2(n - 20)=0 therefore; (n + 2) (n- 20)=0 Hence n = -2,20 4/21/2014 | Elisha A. Comment
n ^2 = 18n + 40 n ^2 - 18n - 40 = 0 n^2 + 2n - 20n - 40 =0 n ( n +2 ) - 20 ( n + 2 ) = 0 ( n + 2 ) ( n - 20 ) = 0 n + 2 = 0 , n = - 2 n -20 = 0 ,n = 20 4/20/2014 | Parviz F. Comment