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he quadratic equation 2x^2 + bx + 18 = x^2 + 9 has a double root. Find all possible values of b.

 Apr 2, 2022
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A quadratic has a double root when the discriminant \(b^2-4ac\) is equal to \(0\).

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Rearraging the equation grants \(x^2+bx+9=0 \Longrightarrow\) \(a = 1, b = b, c = 9\)

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\(b^2 - 4(1)(9) = 0\)

\(b^2 = 36\\ b = \boxed{\pm 6}\)

 

 

 

 

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 Apr 2, 2022

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