The interval in which the function $f(x)

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Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

The interval in which the function $f(x)=10-6 x-2 x^2$ is decreasing is:

Options:

$\left(\frac{-3}{2}, \frac{3}{2}\right)$

$\left(-\infty, \frac{-3}{2}\right)$

$\left(\frac{-3}{2}, \infty\right)$

$\left(-\infty, \frac{3}{2}\right)$

Correct Answer:

$\left(\frac{-3}{2}, \infty\right)$

Explanation:

The correct answer is Option (3) - $\left(\frac{-3}{2}, \infty\right)$

$f(x)=10-6 x-2 x^2$

$f'(x)=-6-4x=0⇒4x=-6$

$x=\frac{-3}{2}$