English | Español

Try our Free Online Math Solver!

Online Math Solver

 

 

 

 

 

 

 

 
 
 
 
 
 
 
 
 

 

 

 
 
 
 
 
 
 
 
 

Please use this form if you would like
to have this math solver on your website,
free of charge.


Solving Quadratic Inequalities

Example: Solve 3x2 + 3x - 6 < 0

Step 1: Go to and under Y1 enter
3x2 + 3x - 6.
Press .
You are graphing a quadratic function,
so the graph should be a parabola .
Step 2: You want to de termine where
the quadratic function is less than 0.
So you need to look at the graph and
determine what part of the graph lies
be low the x -axis or the line y = 0.
Step 3: The part of the graph that is
below the x-axis is the part that lies
between the x-intercepts.

To find these x- intercepts or zeroes ,
go to , the CALCULATE
menu, and select 2: zero.
Press .

To find the intercept on the left , use
the arrow keys to move the cursor to
the left of the point, press .
Then move the cursor to the right of
the point, press , and then
press
again.
The x-intercept is x= -2.

To find the intercept on the right, go
to , the CALCULATE
menu, and select 2: zero.
Press .

Then repeat the process used above.
The other intercept is x = 1.
Step 4: Remember - since you are
solving an inequality , the solution will
be an interval or the union of two
intervals.

The solution to this inequality is the
interval
(-2, 1) or -2 < x < 1.
  Step 5: If you want to determine
where a quadratic is greater than 0,
you need to look at the graph and
determine what part of the graph lies
above the x-axis.
Prev Next