Week 11 in Precalculus

This week in Precalc 11 we learned how to solve a quadratic inequality with one variable using a sign Chart.

The steps when using a sign chart is to:

1. Factor expression

2. Determine zeros

3. Use a sign chart for each factor

for example, take this equation and make it equal to zero the  factor.

Once you have factored determine the zeros (-3/2 and 4) and place them on two number line. Each number line will represent a different factor. One will be (2x+3) and one will be (x-4).

For each factor do a test point in all 3 sections. Pick a point less than  -3/4, between -3/4 and 4, and greater than 4.  Plug these test points in to the factor and determine whether the outcome is negative or positive.

 

Add up the positives and negative of the two number lines to determine what the equation will finally equal.

Since the equation is asking for the equation to be less than zero we want x to be negative.