Function Evaluation
Given the function f(x)=7x4\displaystyle {f{{\left({x}\right)}}}=-{7}{x}-{4} evaluate each of the following using substitution.

Simplify your answer.
f(x2)=\displaystyle {f{{\left({x}-{2}\right)}}}=
 
f(x)=\displaystyle {f{{\left(-{x}\right)}}}=
 
f(5x)=\displaystyle {f{{\left(\frac{{5}}{{x}}\right)}}}=