Answer:
the first one
Step-by-step explanation:
Put the value of x to the inequality:

Answer:
The distance formula is 
The midpoint formula is 
Step-by-step explanation:
apply the pythagorean theorem on a coordinate grid
D, Each x value has one and only one y value.; This is because if an x-value repeats itself then it is not a function. You can test this on a graph by drawing a vertical line on it. If the vertical line intercepts the line more than once anywhere on the graph, then it is not a function.