Question

if -1/2 is one root of quadratic equation 2x^2+kx+1=0 then the value of k is
K=?

Answer 1

$\huge{\mathcal{\green{\underline{Answer}}}}$

$2x {}^{2} + kx + 1 = 0 \\ 2( \frac{ - 1}{2} ) {}^{2} + k( \frac{ - 1}{2} ) + 1 = 0 \\ 2( \frac{1}{4} ) - \frac{k}{2} + 1 = 0 \\ \frac{1}{2} - \frac{k}{2} + 1 = 0 \\ \frac{1 - k + 2}{2} = 0 \\ 1 - k + 2 = 0 \\ - k + 3 = 0 \\ - k = - 3$

$\huge{\mathcal{\green{\implies{\underline{k=3}}}}}$