+0  
 
0
89
1
avatar

OK, I'm going through my lab final - I'm having a difficult time with ALL OF IT...LOL  Yes, I'm not good at higher math.  And this is probably basic algebra....

 

My question is x-2x^1/2-3= 0  and use u substitution. My answer is x=9

Guest May 13, 2017
Sort: 

1+0 Answers

 #1
avatar+75287 
+1

x- 2x^(1/2) - 3= 0

 

Let x = u^2  ...so.....x^(1/2)  =  u   and we have

 

u^2  - 2u - 3  = 0           factor

 

(u - 3)  ( u + 1)  = 0      set both factors  equal to 0 and solve

 

u - 3  = 0                                u +  1    = 0

 

add 3 to both sides            subtract 1 from both sides

 

u  = 3                                 u  = -1

 

So

 

u^2  = 3^2  = 9  = x       or       u^2 = (-1)^2  =  1  = x

 

The second solution makes the original problem false......so...... x = 9  is the only solution

 

 

 

cool cool cool

CPhill  May 13, 2017
edited by CPhill  May 13, 2017

8 Online Users

avatar
avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details