Question

The function f(x) = -2x^5 + x^3 - 7x is an odd function. Which rule is satisfied by this function?
A. f(x) = f(-x)
B. f(x) = -f(x)
C. -f(x) = f(-x)
D. f(x) = f(x)^-1

Answer 1

$f(x) = -2x^5 +x^3 -7x \\\\-f(x) =-(-2x^5 +x^3 -7x) = 2x^5 -x^3 +7x = x(2x^4 - x^2 +7)\\\\f(-x) = -2(-x)^5 + (-x)^3 -7(-x) = 2x^5 -x^3 +7x = x(2x^4 -x^2 +7) \\\\\\\text{Hence,} ~ -f(x)=f(-x)$