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avatar+3654 

Help. 

find all the zeros in each equation 

NotSoSmart  Nov 21, 2017
 #1
avatar+91162 
+2

x^3 - x^2 +5x - 5  = 0     factor as

 

x^2 ( x - 1) + 5 (x - 1)  = 0

 

(x - 1) (x^2 + 5)  =  0  

 

So

 

x - 1  = 0                    and      x^2  + 5 =  0

x  = 1                                     x^2  =  - 5

                                              x  =  ± i √ 5

 

The first answer is correct

 

7x^2  - 144  =  -x^4       rearrange as

 

x^4   + 7x^2  -  144  = 0    factor as

 

(x^2 + 16) ( x^2 - 9)  = 0

 

So

 

x^2 +  16  = 0        and          x^2  - 9  = 9

x^2  =  -16                             x^2  =  9

x = ± 4i                                   x  =  ±3

 

The third answer is correct

 

 

cool cool cool

CPhill  Nov 21, 2017

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