SOLUTION: Given f(x) = –x3 – 2x2 – x – 3, find f(–2), f(0), and f(2)

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: Given f(x) = –x3 – 2x2 – x – 3, find f(–2), f(0), and f(2)      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 92249: Given f(x) = –x3 – 2x2 – x – 3, find f(–2), f(0), and f(2)
Found 2 solutions by jim_thompson5910, checkley71:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Lets evaluate f%28-2%29

f%28x%29=x%5E3-2x%5E2-x-3 Start with the given polynomial


f%28-2%29=%28-2%29%5E3-2%28-2%29%5E2-%28-2%29-3 Plug in x=-2


f%28-2%29=%28-8%29-2%28-2%29%5E2-%28-2%29-3 Raise -2 to the third power to get -8


f%28-2%29=%28-8%29-2%284%29-%28-2%29-3 Raise -2 to the second power to get 4


f%28-2%29=%28-8%29-8-%28-2%29-3 Multiply 2 by 4 to get 8


f%28-2%29=-8-8%2B2-3 Negate any negatives


f%28-2%29=-17 Now combine like terms


So when x=-2, f%28-2%29=-17










Lets evaluate f%280%29

f%28x%29=x%5E3-2x%5E2-x-3 Start with the given polynomial


f%280%29=%280%29%5E3-2%280%29%5E2-%280%29-3 Plug in x=0


f%280%29=%280%29-2%280%29%5E2-%280%29-3 Raise 0 to the third power to get 0


f%280%29=%280%29-2%280%29-%280%29-3 Raise 0 to the second power to get 0


f%280%29=%280%29-0-%280%29-3 Multiply 2 by 0 to get 0


f%280%29=-3 Remove any zero terms


So when x=0, f%280%29=-3







Lets evaluate f%282%29

f%28x%29=x%5E3-2x%5E2-x-3 Start with the given polynomial


f%282%29=%282%29%5E3-2%282%29%5E2-%282%29-3 Plug in x=2


f%282%29=%288%29-2%282%29%5E2-%282%29-3 Raise 2 to the third power to get 8


f%282%29=%288%29-2%284%29-%282%29-3 Raise 2 to the second power to get 4


f%282%29=%288%29-8-%282%29-3 Multiply 2 by 4 to get 8


f%282%29=-5 Now combine like terms

Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=-x^3-2x^2-x-3
f(-2)=-(-2)^3-2(-2^2)-(-2)-3
f(-2)=-(-8)-2(4)+2-3
f(-2)=8-8+2-3
f(-2)=-1
-----------------------------
just replace x with 0 then 2 & solve the same way.