## Exploring inequalities: Graph y< -x^2 + 4 on coord. plane

Complex numbers, rational functions, logarithms, sequences and series, matrix operations, etc.
nghiale2016
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Joined: Sun Sep 27, 2009 9:37 pm
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### Exploring inequalities: Graph y< -x^2 + 4 on coord. plane

Here is the problem
Graph y< -x^2 + 4 on a coordinate plane. Let y= 0 and solve for x and graph the solution a number line. Explain the relationship between the coordinate plane graph and the number line graph.

stapel_eliz
Posts: 1628
Joined: Mon Dec 08, 2008 4:22 pm
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Where are you stuck in the process?

You've graphed the line "y = -x2 + 4" (but as a dashed line, because this is not an "or equal to" inequality), you've plugged zero in for y and solved the quadratic equation for the values of x (being the x-intercepts of the graph), have picked the interval which solves the quadratic inequality, compared this interval with the graph, and... then what?

Please be specific. Thank you!

nghiale2016
Posts: 3
Joined: Sun Sep 27, 2009 9:37 pm
Contact:

### Re: Exploring inequalities: Graph y< -x^2 + 4 on coord. plane

The direction only said that I have to explain the relationship between the coordinate plane graph and the number line graph, I do not know how to do that :(, please help :(

stapel_eliz
Posts: 1628
Joined: Mon Dec 08, 2008 4:22 pm
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You're to explain, after you've done the graph and the number line. What you need to do, once you've done the graph and the number line, is compare the graph's below-the-axis interval with the number line's solution interval.