Question 48097: if f(x)=x(x+1)(x-4), use iterval notation to give all values of x where f(x)>0
i come up with (-1,4) am i missing something ? thank you.
Answer by cowess(34)   (Show Source):
You can put this solution on YOUR website! f(x)=x(x+1)(x-4),
your answer is incorrect because when x= 0 or -1 or 4, f(0)=f(-1)=f(4)=0
for the trigonomial f(x)to be positive(>0)
the three factors in this trigonomial x,(x+1),(x-4) should be
1)all three are positive, their product is positive.
2)two are negative and one positive, their product is also positive.
ANS: x>4 (x,(x+1),(x-4) all >0)
or -10 and x,(x-4)<0)
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