Por favor su ayuda con esas dos ecuaciones?

¡Buenas!

1)

<img src="https://tex.z-dn.net/?f=%20f%28x%29%3D%20%5Csqrt%7Bx%5E%7B2%7D%2B4x%2B4%7D%20%5C%5C%20%5C%5C%20f%28x%29%3D%5Csqrt%7B%28x%2B2%29%5E%7B2%7D%7D%20%5C%5C%20%5C%5C%20f%28x%29%3D%20%7Cx%2B2%7C%20" />

2)

<img src="https://tex.z-dn.net/?f=%20f%28x%29%3D%5Csqrt%7B-x%5E%7B2%7D%2B6x-8%7D%20%5C%5C%20%5C%5C%20f%28x%29%3D%20%5Csqrt%7B-%28x%5E%7B2%7D-6x%2B8%29%7D%5C%5C%20%20%5C%5C%20f%28x%29%3D%20%5Csqrt%7B-%28x%5E%7B2%7D-6x%2B8%2B1-1%29%7D%5C%5C%20%5C%5C%20f%28x%29%3D%20%5Csqrt%7B-%28x%5E%7B2%7D-6x%2B9-1%29%7D%5C%5C%20%5C%5C%20f%28x%29%3D%20%5Csqrt%7B-%5B%28x-3%29%5E%7B2%7D-1%5D%7D%5C%5C%20%5C%5C%20%20f%28x%29%3D%20%5Csqrt%7B-%28x-3%29%5E%7B2%7D%2B1%7D%5C%5C%20%5C%5C%20%5Cmathbf%7BVamos%5C%20a%5C%20buscar%5C%20el%5C%20dominio%7D%5C%5C%20%5C%5C%20f%28x%29%3D%5Csqrt%7B%284-x%29%28x-2%29%7D%20%5C%5C%20%5C%5C%20%284-x%29%28x-2%29%20%5Cgeq%200%20%5C%5C%20%5C%5C%20%5Ctextrm%7BMultiplicamos%20por%20menos%20ambas%20partes%2C%20cambia%20el%20sentido%7D%5C%5C%20%5Ctextrm%7Bde%20la%20desigualdad.%7D%5C%5C%20%20%20%5C%5C%20%28x-4%29%28x-2%29%20%5Cleq%200%20%5C%5C%20%5C%5C%20x%5C%20%5Cin%5C%20%5B2%3B%5C%204%5D%5C%5C%20%5C%5C%20Dom_%7Bf%7D%5C%20%5Cin%5C%20%5B2%3B%5C%204%5D%20" />.