Dado f(x) = 4 elevado a x, demostrar que f(x + 1) - f(x) = 3f(x)?

<img src="https://tex.z-dn.net/?f=f%28x%29%3D4%5Ex" />

<img src="https://tex.z-dn.net/?f=f%28x%2B1%29%2Bf%28x%29%3D4%5E%7Bx%2B1%7D-4%5Ex%5C%5C%20%0Af%28x%2B1%29%2Bf%28x%29%3D4%5Ex%284%29-4%5Ex%5C%5C%20%0Af%28x%2B1%29%2Bf%28x%29%3D4%5Ex%284-1%29%5C%5C%20%0Af%28x%2B1%29%2Bf%28x%29%3D4%5Ex%283%29%5C%5C%20%0Af%28x%2B1%29%2Bf%28x%29%3D3f%28x%29" />

debes aplicar leyes de exponentes

<img src="https://tex.z-dn.net/?f=a%5E%7Bx%2By%7D%20%3D%20a%5Exa%5Ey" />.