Derivative Calculus

I just need my answers checked.

1) Find the derivative.

f(x)=3x^5/4 - 8/9x^9/8 + x^2 - 9x + 1

Answer: f’(x)= 15/4x^1/4 - x ^1/8 + 2x -9

2) Let f(x)= 7x^3 - 9x. Find f’(5)

Answer: f’(x)=21x^2-9
f’(5)=516

3) Find the given limit by evaluating the derivative.

lim h⇒0 5(7+h)^2 - (7+h)-238

Answer: 69

4) Find the slope and an equation of the tangent line to the graph of the function f at the specified point.

f(x)=-1/3x^2+5x+5: (-1, -1/3)

Answer: f’(x)=-2/3x + 5

y=-2/3x -1

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  1. correct.

  2. for #4 I get a slope of 17/3 not -2/3

    (-2/3)(-1) + 5 = 17/3

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  3. Thanks. I will check my answer.

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  4. coreectttttttttttttttt dear

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