Question

Find the derivative of f(x) = negative 9 divided by x at x = -8.

Answer 1

write it in index form

\[f(x) = -9x^{-1}\]

now find the derivative

lastly substitute x = -8 into the derivative

Answer 2

\(\dfrac{d}{dx} x^n = n x^{n - 1} \)

Answer 3

my answer choices are:
8/9
9/8
64/9
9/64

Answer 4

when i did the equation you gave me i got 9/8 is that right??

Answer 5

Can you first use the formula to find the derivative? Then we'll find the value.

Answer 6

well what does your derivative look like...?

Answer 7

9/8 i did -9(-8)^-1

Answer 8

well remember you have to subtract 1 from the power of x

so

\[f'(x) = 9x^{-2}...or.....f'(x) = \frac{9}{x^2}\]

now substitute x = -8

Answer 9

9/64

Answer 10

\(f(x) = -\dfrac{9}{x} \)

\(f(x) = -9x^{-1} \)

\(f'(x) = -1(-9)x^{-2} \)

\(f'(x) = 9x^{-2} \)

\(f'(x) = \dfrac{9}{x^2} \)

\(f'(8) = \dfrac{9}{8^2} = \dfrac{9}{64} \)

You are correct.

Answer 11

thx

Answer 12

wlcm