Logarithms

Log (402 - 202) is equal to

  1. log 3
  2. log 60 + log 20
  3. log 40 – log 20
  4. log 20

Solution

(a- b2) = (a-b)(a+b)

(402 - 202) = (40-20)(40+20) = 20*60

Now using product property of log

Log (a*b) = Log a + Log b 

Log (20*60) = Log 20 + Log 60

Correct option is B.