+0  
 
0
290
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
 #1
avatar+92808 
+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

12 Online Users

avatar
avatar

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.