Maths Help needed Pleeaassseeeee;)

  • 1 vote

Hey Guys...!

can anyone help me with this maths question please can't get the right answer somehow been stuck on it for ages ;/

√13 + 5

----------------------

√13 - √5

any help would be greatly appreciated thanks :)

p.s. please can you show the method it would be of great help ;) thanks ***

Posted Wed 12th September, 2012 @ 18:44 by Muzz :P

7 Answers

  • 2 votes

Have you got to rationalise the bottom line or what is the question??

Answered Wed 12th September, 2012 @ 21:17 by Former Member
  • 2 votes

oh sorry yeah forgot lol

errr we nneed to rationalise the denominator

Answered Wed 12th September, 2012 @ 21:30 by Muzz :P
  • 2 votes

(√13 + 5)              (√13-√5)                              

-----------      x     ---------------        times the bottom and top by   (√13-√5)  

(√13-√5)               (√13-√5)                              

 

 

 

     √169 - √65 + 5√13 - 5√5

=    --------------------------------- Expand the brackets

           √169-√25

 

 

=            √169-√65 +5√13-5√5

                -------------------------      Simplify

                              13-5

 

=             √169-√65 +5√13-5√5

                -------------------------      Should be your answer!! - Does this look right?

                                8

Answered Thu 13th September, 2012 @ 06:11 by Former Member
Edited by Former Member on Thu 13th September, 2012 @ 06:41
  • 2 votes

If you try adding like terms together on the last line and also dividing by 2 to get 4 on the bottom, you should be able to get the answer. 

√169 = 13, √65 = 5√13 or 13√5 - if you play around with the numbers you should get there!!

Answered Thu 13th September, 2012 @ 17:51 by Former Member
  • 1 vote

ok thanks v. much for your help... really appreciate it.. :D x

Answered Thu 13th September, 2012 @ 18:12 by Muzz :P
  • 0 votes

thanks ;) but the answer in the book said

9+ √55

---------

     4      

the answer i got was 18

                                                ------

                                                   8

Answered Thu 13th September, 2012 @ 17:10 by Muzz :P
Edited by Muzz :P on Thu 13th September, 2012 @ 17:10
  • 0 votes

no problem!

Answered Thu 13th September, 2012 @ 18:14 by Former Member