Question

Please help!
Find f(-x)-f(x) for the following function:
f(x)=x^3+x-9

Answer 1

What is f(-x)?

Answer 2

The question didn't say and so I'm stuck.

Answer 3

\(f(3)=3^2+3-9=27+3-9=21\)
\(f(-3)=(-3)^2+(-3)-9=-27-3-9=-39\)
\(-39-21=-60\)
now try it with just \(x\) and \(-x\)

Answer 4

\(f(-x)\) is confusing, but it means replace \(x\) everywhere by \(-x\)

Answer 5

so first step is to write \(f(-x)= (-x)^3+(-x)-9\) and then simplify a big
take that answer, and subtract \(x^3+x-9\) from it
make sure to use parentheses

Answer 6

So it would be -x-x-9-(x^2+x-9)?

Answer 7

i assume you mean
\[-x^3-x-9-(x^3+x-9)\]

Answer 8

Yes.

Answer 9

ok good, now remove the parentheses by distributing the minus sign, then combine like terms

Answer 10

Thank you!

Answer 11

yw hope it is clear