If 7^k + 7^k = (7^9)^(7^9) - 7^k, then k = ? Choose the correct choice
A) 11/3
B) 11/2
C) 242
D) 3^10
E) 7^11 - 1
7^k + 7^k = (7^9)^7^9 - 7^k   7*(7^k) = 7 ^ (49 * 7^9 ) = 7^(7^2 * 7^9) = 7^(7^11)   7^k+1 = 7^(7^11)   So k+1 = 7^11   So k = 7^11 -1   Answer is 7^11 - 1
<result>E</result>
If 7^k + 7^k = (7^9)^(7^9) - 7^k, then k = ?