If loga x = s and loga y = t, then loga (xy)^2

If loga x = s and loga y = t, then loga (xy)2 = ?

  1. 2(s + t)
  2. s + t
  3. 4st
  4. 2st
  5. st

Answer

The correct answer is A.

By properties of logarithms,

loga (xy)2 = 2 loga (xy)

= 2(loga x + loga y)

= 2(s + t)