Given that f(x)=x27x\displaystyle {f{{\left({x}\right)}}}={x}^{{2}}-{7}{x} and g(x)=2x9\displaystyle {g{{\left({x}\right)}}}={2}{x}-{9}, find
(a) (f+g)(4)\displaystyle {\left({f}+{g}\right)}{\left(-{4}\right)}=  
(b) (fg)(4)\displaystyle {\left({f}-{g}\right)}{\left(-{4}\right)}=  
(c) (fg)(4)\displaystyle {\left({f}{g}\right)}{\left(-{4}\right)}=  
(d) (fg)(4)\displaystyle {\left(\frac{{f}}{{g}}\right)}{\left(-{4}\right)}=