indices (O-level revision)

• lolaminx

  17 Oct 08, 20:15

  hi guys, i'm doing my revision for the topic indices, and i have a couple of questions that i'm having trouble with. hope you guys could help out abit. thanks!

   

  *all questions to solve x.

   

  question 1:

  2x to power -3 = 64

  Answer is 1/8.

  
  

  question 2:

  3 to power x = 81 to power 2x

  Answer is 0.

   

  question 3:

  87 to power (2x-5) = 49 / (7 square)

   

  question 4:

  x to power 1/3 = 2

   

  *and a small note: i visited maths-tuition.com and apparently, the website is down. just for heads up.

• ^tamago^

  17 Oct 08, 20:28

  Certain steps seem long for sake of clarity. Skip if you understand the intermediate steps.
  
  
  
  
  
  
  
  

• 4794

  17 Oct 08, 20:36

  question 1, (2x)^-3=64

                      2^-3x^-3=64

                      1/8x^3=64

                       1/x^3=64x8

                        1/x=8,x=1/8

  question 2  3^x=81^2x

                      3^x=3^8x

                      x=7x,0=7x than x=0

  question 3,i don know lol

  question 4, x^1/3=2

                    x=cube root of 2