Question

What’s the domain and range of this graph?

Answer 1

Given:

The graph of a downward parabola.

To find:

The domain and range of the graph.

Solution:

Domain is the set of x-values or input values and range is the set of y-values or output values.

The graph represents a downward parabola and domain of a downward parabola is always the set of real numbers because they are defined for all real values of x.

Domain = R

Domain = (-∞,∞)

The maximum point of a downward parabola is the vertex. The range of the downward parabola is always the set of all real number which are less than or equal to the y-coordinate of the vertex.

From the graph it is clear that the vertex of the parabola is at point (5,-4). So, value of function cannot be greater than -4.

Range = All real numbers less than or equal to -4.

Range =  (-∞,-4]

Therefore, the domain of the graph is (-∞,∞) and the range of the graph is (-∞,-4].