Question

find the derivative of f(x) = -12x^2 9x at x = 6.

Answer 1

Hello,

f(x)=-12x²+9x
f'(x)=-24x+9
f'(6)=-24*6+9=-135

Answer 2

Answer:  The required value of the derivative is -135.

Step-by-step explanation:  We are given to find the derivative of the function f(x) defined as follows :

$f(x)=-12x^2+9x~~\textup{at }x=6.$

We have

$f(x)=-12x^2+9x.$

Differentiating both sides with respect to x, we have

$\dfrac{d}{dx}f(x)=\dfrac{d}{dx}(-12x^2+9x)=-12\times2x+9=-24x+9.$

Therefore, at x = 6, we get

$\dfrac{d}{dx}f(x)=-24\times6+9=-144+9=-135.$

Thus, the required value of the derivative is -135.