Question

if x= 5/2 is a zero of polynomial 2x^2-kx-12,then find the value of k​

Answer 1

Answer:

$\frac{1}{5}$

Explanation:

$x=\frac{5}{2}\\\\p(x)=2x^{2}-kx-12\\p(\frac{5}{2})=(2*\frac{5}{2}*\frac{5}{2})-(k*\frac{5}{2})-12\\p(\frac{5}{2})=(\frac{5}{2}*5)-\frac{5k}{2}-12\\p(\frac{5}{2})=\frac{25}{2}-\frac{5k}{2}-12\\\\LCM=2\\\\\frac{25}{2}-\frac{5k}{2}-\frac{24}{2}=0\\\frac{25-5k-24}{2}=0\\\frac{1-5k}{2}=0\\1-5k=0\\-5k=0-1\\-5k=-1\\k=\frac{-1}{-5}\\k=\frac{1}{5}$

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