<img src="https://tex.z-dn.net/?f=f%28x%29%3D%20%5Cfrac%7B1%7D%7B10%7D-x%20" />
<img src="https://tex.z-dn.net/?f=g%28x%29%3D%20%5Csqrt%7B12%2Bx%7D%20" />
<img src="https://tex.z-dn.net/?f=%28fog%29%28_%7Bx%7D%29%3Df%28g%28x%29%29%3Df%28%20%5Csqrt%7B12%2Bx%7D%29" /> ↓
Este valor sustituyo en la funcnion f(x)
<img src="https://tex.z-dn.net/?f=f%28x%29%3D%20%5Cfrac%7B1%7D%7B10%7D-x%20" />
<img src="https://tex.z-dn.net/?f=f%28%20%5Csqrt%7B12%2Bx%7D%29%3D%20%5Cfrac%7B1%7D%7B10%7D-%20%28%5Csqrt%7B12%2Bx%7D%29%20%0A" />
<img src="https://tex.z-dn.net/?f=%28fog%29%28_%7Bx%7D%29%3D%20%5Cfrac%7B1%7D%7B10%7D-%20%28%5Csqrt%7B12%2Bx%7D%29" />
<img src="https://tex.z-dn.net/?f=%28fog%29%28_%7Bx%7D%29%3D%20%20%5Cfrac%7B1-10%20%5Csqrt%7B12%2Bx%7D%20%7D%7B10%7D%20" />
Dominio
Lo que esta dentro de la raiz debe ser mayor o igual a cero por no existe raiz de indice par en el campo de los reales (IRe)
<img src="https://tex.z-dn.net/?f=%5Cfrac%7B1-10%20%5Csqrt%7B12%2Bx%7D%20%7D%7B10%7D" />
<img src="https://tex.z-dn.net/?f=%2012%2Bx%5Cgeq0%20" />
<img src="https://tex.z-dn.net/?f=x%20%5Cgeq%20-12" />
Si e X es mayor que - 12
D.
X∈[ - 12, + ∞).