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Question 322443: Solve.
(x+15)(x-10)(x+5)>0
Thank you very much!!!
Answer by vleith(2983)   (Show Source):
You can put this solution on YOUR website! Try to plot it.
You know you have zeroes at x = 1-5, x = -5 and x=10
Pick a number greater than 10 (let's say 20). Plug that in and see that as x gets larger than 10, the solution gets more postive. So the curve rises to the right.
Pick a number between -5 and 10 (pick 0 for instance). Solve that and see that that answer is less than 0. So the curve is below the x axis between -5 and 10.
Pick a number between -15 and -5 (lit's use -10). Solve that and see the curve is above the x axis between -15 and -5.
Pick a larger negative number (lets say -20) and see the answer lies below the x axis. Also, as x gets more negative, the reuslting point lies farther below the x axis. So the curve talis off to negative infinity .
Now color in the places where the curve is above the x axis. That is -1510
Here is a plot for you
http://www.wolframalpha.com/input/?i=%28x%2B15%29%28x-10%29%28x%2B5%29%3E0+
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