find the domain and express the domain in interval notation. its only for the top two problems.

Question:
find the domain and express the domain in interval notation.
[tex]g(x)\text{ = }\sqrt[]{7-x}[/tex]Solution:
Since we have a square root. Then the part inside the square root must be positive, that is:
[tex]7\text{ -x}\ge0[/tex]this is equivalent to:
[tex]\text{ -x}\ge-7[/tex]this is equivalent to:
[tex]\text{ x }\leq7[/tex]then, the domain of this function is :
[tex](\infty,7\rbrack[/tex]