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One of the roots of 2x^2 + rx + s = 0 is 5 - 3i, where r and s are real.  Find r + s.

 May 30, 2020
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If one root is  5 - 3i  then the other root is  5 + 3i.

 

An equation with these roots are:  [ x - (5 - 3i) ] · [ x - (5 + 3i) ]  =  0

 

Expand this equation.

 

However, the equation is supposed to be of the form:  2x2 + rx + s  =  0,

so, you'll have to multiply your answer (above) by 2 to get the proper form.

Then, you'll have r and s.

 May 31, 2020

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