Find the derivative of f(x) = 12x2 + 8x at x = 9. 256 -243 288 224 i answer questions for you but no one ever answers my questions. you're all are so ungrateful. i've been trying to find the answer for several hours and nothing. yes i did try to teach myself but i just cant understand it.

It's 224.

Step-by-step explanation:

We use the power rule for a derivative.

If f(x) = ax^n then the derivative  f'(x) = anx^(n-1).

So the derivative of 12x^2 + 8x

= 2*12 x^(2-1) + 8x^(1-1)

= 24x + 8x^0

= 24x + 8.

When x = 9 the derivative = 24(9) + 8

=  224.

the answer is 62.8 cubic units

- (2, -7)

- lines r and s and lines t and u must be parallel