What is the domain and range of f(x) = 2x^2 - 3?

1 Answer
Kiri B.
Feb 1, 2018

graph{2x^2-3 [-10.07, 9.93, -3.86, 6.14]} So this shown above uarr is the graph for f(x)=2x^2-3.
Domain: x=oo
Range: y > -3

Explanation:

The definition of domain is the set of x values on the graph. The definition of the range is the set of y values on a graph.
So when you look at the domain you look at the x-axis (horizontal line). So where does the line stop and start on the x-axis? it goes on forever right? Because the side keeps expanding forever and ever so the domain would equal oo ... Now let's look at the range. The range is the set of y-values so if you have a paper on this tilt it so it's easier to see it looks like a big arrow, <. So the tip of this "arrow" touches -3 and then goes on forever and ever...
so you can either put y>-3 (y is bigger than negative 3) or,
-3 < y < oo (-3 is smaller than y but goes on forever).
Hope this was understandable please comment below if you have concerns...

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