SOLUTION: Solve the inequality x^2-4+(3/x)< 0 What I have tried: (x^3-4x+3)/x < 0 I do not know how to proceed after this. Thank you in advance

Algebra ->  Graphs -> SOLUTION: Solve the inequality x^2-4+(3/x)< 0 What I have tried: (x^3-4x+3)/x < 0 I do not know how to proceed after this. Thank you in advance       Log On


   



Question 981172: Solve the inequality
x^2-4+(3/x)< 0
What I have tried:
(x^3-4x+3)/x < 0
I do not know how to proceed after this.
Thank you in advance

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2-4%2B%283%2Fx%29%3C+0

and your correct step giving
%28x%5E3-4x%2B3%29%2Fx+%3C+0


This inequality has possibly four critical x values:
0, and whatever are the "roots" of the numerator.

Rational Roots Theorem and Synthetic Division will give only %28x-1%29 as factor, and then quadratic factor will have roots %28-1%2B-+sqrt%2813%29%29%2F2;
The other zero is 0, for which the equation is undefined.

Check any value within these five intervals:
(-infinity, -2.3025), the right limit being decimal approximation for irrational;
(-2.3025,0);
(0,1);
(1, 1.3025), again right limit is decimal approximation;
(1.3025, infinity).

Find if the value in the interval makes the original inequality true or false.


Here is a graph of the left member just as a check for your efforts checking in each interval.
graph%28300%2C300%2C-3%2C3%2C-4%2C4%2Cx%5E2-4%2B3%2Fx%29

A close-up of one area of the graph:
graph%28300%2C300%2C-0%2C2%2C-1%2C2%2Cx%5E2-4%2B3%2Fx%29

--
What you should find:
(-infinity, -2.3025), False
(-2.3025,0), True;
(0,1), False;
(1, 1.3025), True;
(1.3025, infinity), False