SOLUTION: Calculate the indicated value. f(x) = 7x - 27x^2 - 7 find f(-7) I'm not sure where to start, do I just replace each x with -7? I have a few question like this and if possib

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Calculate the indicated value. f(x) = 7x - 27x^2 - 7 find f(-7) I'm not sure where to start, do I just replace each x with -7? I have a few question like this and if possib      Log On


   

Question 83834: Calculate the indicated value.
f(x) = 7x - 27x^2 - 7
find f(-7)
I'm not sure where to start, do I just replace each x with -7? I have a few question like this and if possible I'd like to see the steps and the answer so I can figure out the rest of my questions. Thank you for your help!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Whenever you see something like f(-7) you just substitute -7 in for x (ie you replace every x with -7) and you evaluate the answer.

f%28-7%29+=+7%28-7%29+-+27%28-7%29%5E2+-+7 Plug in x=-7


f%28-7%29+=+7%28-7%29+-+27%2849%29+-+7 Square -7

f%28-7%29+=+-49+-+1323+-+7 Multiply

f%28-7%29+=+-1%2C379 Combine like terms

So f(-7) is -1,379