maths problem

√(k+3)²+25 = √(8-k)²
Case 1 : k + 3 >= 0 and 8 - k >= 0 :
k+3 + 25 = 8-k
k = - 10 ,
but - 10 + 3 = - 7 < 0 , rejected.
Case 2 : k + 3 >= 0 and 8 - k <= 0 :
k+3 + 25 = k-8
k have no solution.
Case 3 : k + 3 <= 0 and 8 - k >= 0 :
- k - 3 + 25 = 8 - k
k have no solution.
Case 4 : k + 3 <= 0 and 8 - k <= 0 :
- k - 3 + 25 = k - 8
k = 15 ,
But 15 + 3 > 0 , rejected.
The equation have no solution.



2010-04-24 14:54:31 補充：
001 answer is wrong ,

√(k+3)²+25 = √(8-k)²

√(-10+3)²+25 = √(8-(-10))²

√49 + 25 = √324

7 + 25 = 18 is wrong.

√(k+3)²+25 = √(8-k)²
(k+3)+25 = 8-k
k+28 = 8-k
2k = -20
k = -10