If 3 is a root of x^2 + kx - 24 = 0, it is also a root of - Vidyadip

MCQ

If $3$ is a root of ${x^2} + kx - 24 = 0,$ it is also a root of

A
${x^2} + 5x + k = 0$
B
${x^2} - 5x + k = 0$
✓
${x^2} - kx + 6 = 0$
D
${x^2} + kx + 24 = 0$

✓

Answer

Correct option: C.

${x^2} - kx + 6 = 0$

c
(c) Equation ${x^2} + kx - 24 = 0$ has one root is $3.$

$ \Rightarrow \,\,{3^2} - 3k - 24 = 0$ $ \Rightarrow \,\,k = 5$

Put $x = 3$ and $k = 5$ in options, only $(c)$ gives the correct answer.

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