3times a number h means what expression

3h

Step-by-step explanation:

The answer required is an expression.

Multiplying a letter with a number gives an expression.

3 times a number h means:

    3 × h = 3h

The domain of a function is the set of values that are used as the x-coordinate.

As the parabola continues to go up and widen, all real numbers will be used as x-coordinates, so the domain is all real numbers.