log25400=x হলে এক্স x এর মান কত?
A
400
B
10
C
4
D
25
Correct Answer: 4
log25400 = log25202 = log25(4×5)² = log25(25)4 = 4log2525 = 4log2525 = 4×1 = 4.'.x = 4