SOLUTION: Evaluate each function for the value specified 3. f (x) = -2x^3 + 5x^2 - x - 1; find (a) f (-1), (b) f (0), and (c) f (2).

Algebra ->  Graphs -> SOLUTION: Evaluate each function for the value specified 3. f (x) = -2x^3 + 5x^2 - x - 1; find (a) f (-1), (b) f (0), and (c) f (2).       Log On


   

Question 124404: Evaluate each function for the value specified
3. f (x) = -2x^3 + 5x^2 - x - 1; find

(a) f (-1), (b) f (0), and (c) f (2).
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
a)

Let's evaluate f%28-1%29


f%28x%29=-2x%5E3%2B5x%5E2-1x-1 Start with the given function.


f%28-1%29=-2%28-1%29%5E3%2B5%28-1%29%5E2-1%28-1%29-1 Plug in x=-1. In other words, replace each x with -1.


f%28-1%29=-2%28-1%29%2B5%28-1%29%5E2-1%28-1%29-1 Evaluate %28-1%29%5E3 to get -1.


f%28-1%29=-2%28-1%29%2B5%281%29-1%28-1%29-1 Evaluate %28-1%29%5E2 to get 1.


f%28-1%29=%2B2%2B5%281%29-1%28-1%29-1 Multiply -2 and -1 to get 2


f%28-1%29=%2B2%2B5-1%28-1%29-1 Multiply 5 and 1 to get 5


f%28-1%29=%2B2%2B5%2B1-1 Multiply -1 and -1 to get 1


f%28-1%29=7 Now combine like terms


-----------Now let's evaluate another value---------

b)

Let's evaluate f%280%29


f%28x%29=-2x%5E3%2B5x%5E2-1x-1 Start with the given function.


f%280%29=-2%280%29%5E3%2B5%280%29%5E2-1%280%29-1 Plug in x=0. In other words, replace each x with 0.


f%280%29=-2%280%29%2B5%280%29%5E2-1%280%29-1 Evaluate %280%29%5E3 to get 0.


f%280%29=-2%280%29%2B5%280%29-1%280%29-1 Evaluate %280%29%5E2 to get 0.


f%280%29=%2B0%2B5%280%29-1%280%29-1 Multiply -2 and 0 to get 0


f%280%29=%2B0%2B0-1%280%29-1 Multiply 5 and 0 to get 0


f%280%29=%2B0%2B0%2B0-1 Multiply -1 and 0 to get 0


f%280%29=-1 Now combine like terms


-----------Now let's evaluate another value---------

c)

Let's evaluate f%282%29


f%28x%29=-2x%5E3%2B5x%5E2-1x-1 Start with the given function.


f%282%29=-2%282%29%5E3%2B5%282%29%5E2-1%282%29-1 Plug in x=2. In other words, replace each x with 2.


f%282%29=-2%288%29%2B5%282%29%5E2-1%282%29-1 Evaluate %282%29%5E3 to get 8.


f%282%29=-2%288%29%2B5%284%29-1%282%29-1 Evaluate %282%29%5E2 to get 4.


f%282%29=-16%2B5%284%29-1%282%29-1 Multiply -2 and 8 to get -16


f%282%29=-16%2B20-1%282%29-1 Multiply 5 and 4 to get 20


f%282%29=-16%2B20-2-1 Multiply -1 and 2 to get -2


f%282%29=1 Now combine like terms