SOLUTION: If f(x)= x(x+1) (x-4), use interval notation to give all values of x where f(x) >0.

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Question 102561: If f(x)= x(x+1) (x-4), use interval notation to give all values of x where f(x) >0.
Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
f(x) = x(x + 1)(x - 4)
For x = 0, x = -1, and x = 4, f(x) has the value of zero.
<----------(-1)---------(0)-------------------------(4)-------->
Test:
f(-2) = -2(-1)(-6) = -12
f(-1/2) = (-1/2)(1/2)(-9/2) = 9/8
f(1) = (2)(-3) = -6
f(5) = 5(6)(1) = 30
<----------(-1)=========(0)-------------------------(4)========>
f(x) > 0 only satisfied by f(x) > 4 and 0 > f(x) > -1
or
(-1,0)U(4,+inf)
graph%28300%2C300%2C-5%2C5%2C-5%2C5%2Cx%5E3+-+3x%5E2+-+4x%29