Logarithms-13

From Homeworkwiki

Jump to: navigation, search

Find x, if : (i) log 2 x = - 2

(ii) log 4 (x + 3) = 2

(iii) log 9 27 = x

(iv) log x 64 = 3 / 2

(v) log 2 (x 2 - 4) = 5

Solution:

(i) log 2 x = - 2

=> 2 -2 = x

=> x = 1 / 4

(ii) log 4 (x + 3) = 2

=> 4 2 = x + 3

=> x = 16 - 3 = 13

(iii) log 9 27 = x

=> 9 x = 27

=> 3 2x = 3 3

=> x = 3 / 2

(iv) log x 64 = 3 / 2

=> x 3 / 2 = 64

=> x = (64) 2 / 3 = (2 6) 2 / 3 = 16

(v) log 2 (x 2 - 4) = 5

=> 2 5 = x 2 - 4

=> x 2 = 32 + 4 = 36

=> x = ± 6

Personal tools
McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams