SOLUTION: Help ME please!!!! f(x)=-x(cubed)+2x(squared)-7x+9 find (a)f(-2), (b)f(0), and (c)f(2) I appreciate the help Heather

Algebra ->  Linear-equations -> SOLUTION: Help ME please!!!! f(x)=-x(cubed)+2x(squared)-7x+9 find (a)f(-2), (b)f(0), and (c)f(2) I appreciate the help Heather      Log On


   

Question 110897: Help ME please!!!!
f(x)=-x(cubed)+2x(squared)-7x+9
find (a)f(-2), (b)f(0), and (c)f(2)
I appreciate the help
Heather
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

f%28x%29=-1x%5E3%2B2x%5E2-7x%2B9 Start with the given function.



f%28-2%29=-1%28-2%29%5E3%2B2%28-2%29%5E2-7%28-2%29%2B9 Plug in x=-2. In other words, replace each x with -2.

f%28-2%29=-1%28-8%29%2B2%28-2%29%5E2-7%28-2%29%2B9 Evaluate %28-2%29%5E3 to get -8.

f%28-2%29=-1%28-8%29%2B2%284%29-7%28-2%29%2B9 Evaluate %28-2%29%5E2 to get 4.



f%28-2%29=%2B8%2B2%284%29-7%28-2%29%2B9 Multiply -1 and -8 to get 8


f%28-2%29=%2B8%2B8-7%28-2%29%2B9 Multiply 2 and 4 to get 8


f%28-2%29=%2B8%2B8%2B14%2B9 Multiply -7 and -2 to get 14


f%28-2%29=39 Now combine like terms


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


f%28x%29=-1x%5E3%2B2x%5E2-7x%2B9 Start with the given function.



f%280%29=-1%280%29%5E3%2B2%280%29%5E2-7%280%29%2B9 Plug in x=0. In other words, replace each x with 0.

f%280%29=-1%280%29%2B2%280%29%5E2-7%280%29%2B9 Evaluate %280%29%5E3 to get 0.

f%280%29=-1%280%29%2B2%280%29-7%280%29%2B9 Evaluate %280%29%5E2 to get 0.



f%280%29=0%2B2%280%29-7%280%29%2B9 Multiply -1 and 0 to get 0


f%280%29=0%2B0-7%280%29%2B9 Multiply 2 and 0 to get 0


f%280%29=0%2B0%2B0%2B9 Multiply -7 and 0 to get 0


f%280%29=9 Now combine like terms


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


f%28x%29=-1x%5E3%2B2x%5E2-7x%2B9 Start with the given function.



f%282%29=-1%282%29%5E3%2B2%282%29%5E2-7%282%29%2B9 Plug in x=2. In other words, replace each x with 2.

f%282%29=-1%288%29%2B2%282%29%5E2-7%282%29%2B9 Evaluate %282%29%5E3 to get 8.

f%282%29=-1%288%29%2B2%284%29-7%282%29%2B9 Evaluate %282%29%5E2 to get 4.



f%282%29=-8%2B2%284%29-7%282%29%2B9 Multiply -1 and 8 to get -8


f%282%29=-8%2B8-7%282%29%2B9 Multiply 2 and 4 to get 8


f%282%29=-8%2B8-14%2B9 Multiply -7 and 2 to get -14


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