SOLUTION: <img src="http://img110.imageshack.us/img110/6295/mathis8.png"> pleaseeee i neeeeeed help!

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: <img src="http://img110.imageshack.us/img110/6295/mathis8.png"> pleaseeee i neeeeeed help!      Log On


   

Question 115189:


pleaseeee i neeeeeed help!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Since x%2B1 is a factor, this means x=-1 is a zero. In other words, f%28-1%29=%28-1%29%5E7%2Ba%28-1%29-2=0

Now let's solve for a
%28-1%29%5E7%2Ba%28-1%29-2=0 Start with the given equation


-1%2Ba%28-1%29-2=0 Raise -1 to the seventh power


-1-a-2=0 Multiply


-a-3=0 Combine like terms


-3=a Add "a" to both sides


So the value of "a" is a=-3

This means that the function is


f%28x%29=x%5E7-3x-2


Now just plug in x=2 to find f(2)



f%282%29=%282%29%5E7-3%282%29-2 Plug in x=2. In other words, replace each x with 2.


f%282%29=%28128%29-3%282%29-2 Evaluate %282%29%5E7 to get 128.


f%282%29=%28128%29-6-2 Multiply -3 and 2 to get -6


f%282%29=120 Now combine like terms


So our answer is f%282%29=120