Evaluate (fg)(x)\displaystyle {\left({f}\circ{g}\right)}{\left({x}\right)}

f(x)=x2+5x\displaystyle {f{{\left({x}\right)}}}={x}^{{2}}+{5}{x}

g(x)=x4\displaystyle {g{{\left({x}\right)}}}={x}-{4}

(fg)(x)=\displaystyle {\left({f}\circ{g}\right)}{\left({x}\right)}=