check each graph below that represents a function

Explanation:

Step1: Recall vertical - line test

Use the vertical - line test to determine if a graph represents a function. If any vertical line intersects the graph at most once, then the graph represents a function.

Step2: Analyze first graph

For the first graph (a parabola opening upwards), any vertical line will intersect it at most once. So it represents a function.

Step3: Analyze second graph

For the second graph (a horizontal line), any vertical line will intersect it at most once. So it represents a function.

Step4: Analyze third graph

For the third graph (a non - vertical straight line), any vertical line will intersect it at most once. So it represents a function.

Answer:

All of the given graphs represent functions.