One of the things we learned this week in Precalc 11 is how to solve Quadratic Inequalities using a sign chart.
When the question asks, solve this quadratic inequality it’s basically saying, when is the part of the parabola less than 0 and when we look at a graph we can easily answer that.

From -1 through 5 the parabola is less than 0 so -1 < x <5

Solving using a sign chart

1. factor – Factor the expression

2. Determine the Zeros – Determine the zeros

3. Use a sign chart – Create a sign chart for each of the factor (-, 0, +) to the left and right of zeros

Signs/Symbols

● – closed circle, used when the expression is

○ – open circle, used when the expression is < or >

Example