Correct Answer - Option 3 : 2
Properties used
1) nlogm = logmn
2) logm + logn = log(mn)
3) logm - logn = log(m/n)
Calculation
1/2log10625 – 5log102 + log10128
⇒ log106251/2 – log1025 + log10128
⇒ log1025 – log1032 + log10128
⇒ log10[25 × (128/32)]
⇒ log10100
⇒ log10102
⇒ 2log1010
⇒ 2
