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if -5 is a root of the equation 0=x^2-ax-12 what is the other root

 Apr 27, 2021
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if -5 is a root of the equation 0=x^2-ax-12 what is the other root

 

let b be the other root

 

By vieta’s we have -5+b=-(-a)/1 => -5+b=a (EQ 1)

We also have -5b=-12/1 => -5b = -12 (EQ 2)

 

EQ 2 => 5b = 12 => b = 12/5 (EQ 3)

 

(For fun let’s find a)

 

(EQ 3) & (EQ 1) = 12/5 - 5 = a => 12-25 / 5 = a

 

a = -13/5

 

—————

 

ANSWER: 12/5

 

laugh

 Apr 27, 2021

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