Question

Diketahui :log 2 = a, log 3 = b, log 5 = c
dit : a. log 72
b. log √150

Answer 1

Log 2 = a
log 3 = b
log 5 = c

a. log 72 = log 2.2.2. 3.3 = log a.a.a .b.b = log a³ b²

b. log√150 = log 5. √2√3 = c√a√b

Answer 2

A. log 72
  =log ( 8 x 9 )
  =log ( 2³ x 3²)
  =( 3 x log 2) + ( 2 x log 3)
  = 3a + 2b

b. log √( 25 x 3 x 2)
  = log √25 + log√3 + log√2
  = log 5 + log √3 + log √2
  = log 5 + log (3 pangkat 1/2) + log (2 pangkat 1/2)
  = log 5 + 1/2 log3 + 1/2 log 2
  = c + (1/2)b + (1/2)a
  ....(2c + b + a)
   =---------------
.............2