SOLUTION: Hi Can I have some help evaluating this function? Use the function to evaluate the indicated expressions and simplify. f(x) = -2x^2 + 7 f(x + 2) = f(x) + f(2) =

Algebra ->  Equations -> SOLUTION: Hi Can I have some help evaluating this function? Use the function to evaluate the indicated expressions and simplify. f(x) = -2x^2 + 7 f(x + 2) = f(x) + f(2) =       Log On


   

Question 126005: Hi Can I have some help evaluating this function?
Use the function to evaluate the indicated expressions and simplify.
f(x) = -2x^2 + 7
f(x + 2) =
f(x) + f(2) =
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29+=+-2x%5E2+%2B+7+ Start with the given function


f%28x%2B2%29+=+-2%28x%2B2%29%5E2+%2B+7+ Replace each x with x%2B2


f%28x%2B2%29+=+-2%28x%5E2%2B4x%2B4%29%2B+7+ Foil


f%28x%2B2%29+=+-2x%5E2-8x-8%2B+7+ Distribute


f%28x%2B2%29+=+-2x%5E2-8x-1+ Combine like terms



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f%28x%29=-2x%5E2%2B7 Start with the given function


f%282%29=-2%282%29%5E2%2B7 Plug in x=2


f%282%29=-2%2A4%2B7 Raise 2 to the 2nd power to get 4


f%282%29=-8%2B7 Multiply -2 and 4 to get -8


f%282%29=-1 Add -8 and 7 to get -1


Now add f(2) to f(x) to get


f%28x%29%2Bf%282%29=%28-2x%5E2%2B7%29%2B%28-1%29


f%28x%29%2Bf%282%29=-2x%5E2%2B8 Combine like terms