Question

One of the roots of quadratic equation 2x2+kx-2=0 is -2, find k​

Answer 1

$\sf \ \ \alpha+\beta= \dfrac{-b}{a}\\ \\ \\ \sf\ \ \ -2= \dfrac{-k}{2}\\ \\ \\ \sf\ \ \ -4= -k\\ \\ \\ \bf\ \ \ k=4$

Answer 2

Answer:

The value of k is 3...

Step-by-step explanation:

-2 is a root of equation

2x^2 + kx - 2 = 0

Substituting x= -2 in equation

2x^2 + kx - 2 = 0

2×(-2)^2 + k (-2) -2 = 0

2×4+(-2k)-2=0

8-2k-2=0

2k=8-2

2k=6

k=6/2

k=3..........

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