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web2.0 calc did nothin for me

 

what is the solution of

\(\sqrt{5x+4} - \sqrt{x} = 4\)

 Dec 19, 2017
 #1
avatar+107156 
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√ [ 5x + 4 ] - √x  =  4          rearrange as

 

√[5x + 4 ]  =  4 + √x          square both sides

 

5x + 4  =  16  + 8√x  +  x

 

4x - 12  =  8√x           divide both sides by 4

 

x -  3  =  2√x             square both sides again

 

x^2  - 6x  +  9   =   4x

 

x^2  -  10x  +  9   =   0           factor

 

(x - 9) ( x - 1)   = 0

 

Setting both factors to 0  and solving for x leads to two possible solutions :

 

x  = 1     and  x   = 9

 

Checking these in the original equation.....only x  = 9   will be a true solution

 

 

cool cool cool

 Dec 19, 2017

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