Let f(x)=3x\displaystyle {f{{\left({x}\right)}}}={3}^{{x}}

If g(x)\displaystyle {g{{\left({x}\right)}}} is the graph of f(x)\displaystyle {f{{\left({x}\right)}}} shifted right 5 units and reflected across the x-axis, write a formula for g(x)\displaystyle {g{{\left({x}\right)}}}