PLEASE HELP WILL GIVE A MEDAL
Find the derivative of f(x) = 8x + 4 at x = 9.

Question

PLEASE HELP WILL GIVE A MEDAL
Find the derivative of f(x) = 8x + 4 at x = 9.

anonymous · Answer

@freckles

anonymous · Answer

Find the derivative first and then plug in x = 9.
What is the derivative of f(x) = 8x+4

anonymous · Answer

It might be a bit tricky since you have x = 9, once you find the derivative, see what you can say about x.

freckles · Answer

this is just a line 
you could find the derivative easily if you recall some algebra from your algebra days

freckles · Answer

slope=derivative after all

anonymous · Answer

so if the derivative is 8 what do I do with the 9?

freckles · Answer

the derivative is 8 for all x

anonymous · Answer

how would I figure it out if the equation was quadratic?

anonymous · Answer

Find the derivative of f(x) = -4x2 + 11x at x = 10

anonymous · Answer

@freckles

anonymous · Answer

$$f(x)= x^n~~~~\implies f'(x) = nx^{n-1}$$ take the derivative term by term as previously.

anonymous · Answer

I still don't understand

freckles · Answer

to find the derivative of x^2 use the formula @iambatman has given you
notice n is 2 when trying to find the derivative of x^2