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Example Question #1 : Rational Inequalities
Solve
In order to solve this, we need to figure out what values of x makes the numerator and denominator equal zero.
These values are , and
.
Then test a few numbers greater or lesser than the above values to figure out what range of values make the inequality true.
Example Question #2 : Rational Inequalities
Give the solution set of the equation
The boundary points of a rational inequality are the zeroes of the numerator and the denominator.
First, set the numerator equal to 0 and solve for :
Now set the denominator equal to 0 and solve for :
Factor the trinomial using the reverse-FOIL method. Look for two integers whose sum is and whose product is 7; these are
, and
, so the equation can be rewritten as
Set each factor to zero and solve for :
Therefore, the boundary points are , which divide the real numbers into four intervals. Choose any value from each interval as a test point, setting
to that value and determining whether the inequality is true.
The four intervals are listed below, along with their arbitrary test points.
: Set
True; include .
: Set
False; exclude .
: Set
:
True; include
: Set
:
False; exclude .
Since the inequality symbol is the "is greater than or equal to" symbol, include the zero, 0, of the numerator - but not the other two boundaries, the zeroes of the denominator. This makes the solution set
.
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