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The roots of the quadratic equation z^2+bz+c=0 are -7+2i and -7-2i. What is b+c?

 Jun 1, 2021
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By Vieta

 

The  sum of the roots =  -b

So   - b  =      (-7 + 2i)  + (-7 - 2i)  =   -14

So  b =  14

 

Also....the product of the roots =  c

So   c =         (-7 + 2i)  ( -7 - 2i)   =    49 - 4i^2   =  49  - 4(-1)   =   49 + 4  = 53

 

b +  c  =  14  +  53   =   67

 

 

cool cool cool

 Jun 1, 2021

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