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One root of x^2 + 12x + k = 18x + 3 is twice the other root. Find k.

 Jan 31, 2022
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x2 + 12x + k = 18x + 3

x2 - 6x + (k-3) = 0

Let the roots be a, 2a

a + 2a = 6, a(2a) = k-3 => 3a = 6 => a = 2

2a2 = k - 3 => k - 3 = 8 => k = 11.

 Jan 31, 2022

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