Question

Find and simplify f(-x)-f(x) for the given function f.
f(x)=-7x^3-3x^2+9x-20.
f(-x)-f(x)=?

Answer 1

hello

Answer 2

First evaluate f(-x).
That should be \[-7(-x)^{3} - 3(-x)^{2} + 9(-x) -20\]
which evaluates to \[f(-x) =7(x)^{3} - 3(x)^{2} - 9(x) -20\]

now you take f(-x) - f(x)
\[(7(x)^{3} - 3(x)^{2} - 9(x) -20) -( -7(x)^{3} - 3(x)^{2} + 9(x) -20)\]

which equals \[14(x)^{3} - 18(x)\]

Answer 3

thanks :) medalllll

Answer 4

Notice how you are only left only with the odd powered terms are left. That's because their sign becomes positive and those terms are doubled. Even powered terms cancel out.