Question 43896: I just asked a question but was slightly wrong,here is the correct wording: If f(x)=x(x+3)(x-1), use interval notation to give all values of x where f(x) is greater than 0. The last email said less than 0,I typed it wrong. Thanx
Answer by fractalier(6550)   (Show Source):
You can put this solution on YOUR website! A good way to analyze
f(x) = x(x+3)(x-1)
is to set up a number line and plot open points where f(x) equals zero, that is, at x = 0, x = -3, and at x = 1. Open because the requirement is not "or equal to."
Then you test points within each interval (there are four of them) to see if f(x) becomes positive...try x = 2 for example...it works...thus part of the solution is x > 1.
Then try x = 1/2. It doesn't work.
Then try x = -1. That works, so that -3 < x < 0.
Then try x = -5. That doesn't work...
And that is how you analyze this type of problem...
Our solution is
x > 1 or -3 < x < 0.
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