SOLUTION: My question: Find the difference quotient for f(x) = 7x^2-9x+2 This is what I've come up with, I want to make sure I understand it and did it right! f(x+h) = 7(x+h)^2 - 9(x+h)

Algebra ->  Functions -> SOLUTION: My question: Find the difference quotient for f(x) = 7x^2-9x+2 This is what I've come up with, I want to make sure I understand it and did it right! f(x+h) = 7(x+h)^2 - 9(x+h)       Log On


   

Question 515222: My question: Find the difference quotient for f(x) = 7x^2-9x+2
This is what I've come up with, I want to make sure I understand it and did it right!
f(x+h) = 7(x+h)^2 - 9(x+h) + 2
= 7(x+h)(x+h) - 9x-9h + 2
=7[x^2 + 2hx+h^2] - 9x-9h + 2
=7x^2 + 14hx+7h^2-9x-9h+2-(7x^2-9x+2)
=7x^2 + 14hx+7h^2-9x-9h+2-7x^2+9x-2/h
=14hx+7h^2-9h/h
=h(14x+7h-9)/h
=(14x+7h-9) Final Answer!
Wow, these wear me out, I'm praying I did it right or at least close!!
Thanks so much,
Tracy
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
You have the correct answer. Congrats.


One little nit-picky thing to point out. I would write the answer as 14x+7h-9 (ie remove the outer parenthesis as they are not needed). Other than that, everything is perfect.