A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing

This Question is Closed

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1do you know how to rationalize the denominator ?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1multiply the numerator and denominator by the conjugate of denominator here, it'll be 3 \(\sqrt5\) what do u get ?

blackjesus619
 one year ago
Best ResponseYou've already chosen the best response.0What do u get when u multiply it with 7+√5

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1you mean multiply (1+√5) with (3√5) thats your numerator, you just need to foil to simply it.

blackjesus619
 one year ago
Best ResponseYou've already chosen the best response.0Its 7√5 in the question can't multiply it with 3√5 that's the part I get confused with

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1ok, \(7\sqrt 5 \times 3 = 21 \sqrt 5\ \\7\sqrt5\times \sqrt5= 7\sqrt{5^2}=7\times 5=35 \\so \\ 7\sqrt5(3\sqrt5)=21\sqrt535 \) got it ?

blackjesus619
 one year ago
Best ResponseYou've already chosen the best response.0The answer on my answer sheet is 4√5 how do I get that

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1ok, then we were supposed to multiply (7+√5) (and not 7√5 as you mentioned "Its 7√5 in the question") then you actually foil : \((7+√5)(3√5)= 7*3 7√5+3√5√5√5 = 21+(7+3)√55\\=164√5=4(4√5)\) and if you simplify the denominator, you'll get a 4 which cancels with the numerator's 4 and you are just left with 4√5

blackjesus619
 one year ago
Best ResponseYou've already chosen the best response.0I didn't get anything from that sorry but u have confused me a lot

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1i used this \((a+b)(c+d)=ac+ad+bc+bd\) try to do this with (7+√5)(3√5) take 7 multiply it with 3 and √5 then take √5, multiply it with 3 and √5

phi
 one year ago
Best ResponseYou've already chosen the best response.1to go over it: \[ \frac{ 7+\sqrt{5}}{3+\sqrt{5}} \] you multiply top and bottom by \( 3 \sqrt{5} \) \[ \frac{ (7+\sqrt{5})( 3 \sqrt{5})}{(3+\sqrt{5})( 3 \sqrt{5})} \]

phi
 one year ago
Best ResponseYou've already chosen the best response.1now you have two FOIL problems: one on the top and one in the bottom can you do them ? (see hartn's posts on how)

blackjesus619
 one year ago
Best ResponseYou've already chosen the best response.0I don't know how to do the 7+√5 one

phi
 one year ago
Best ResponseYou've already chosen the best response.1to do \[ (7+ \sqrt{5})(3 \sqrt{5} ) \] you do 4 multiplies: the First, Outer, Inner, Last This might help http://www.khanacademy.org/math/algebra/polynomials/multiplying_polynomials/v/multiplyingbinomials
Ask your own question
Ask a QuestionFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.