Week 11- Solving Quadratic Inequalities

This week in math I learned about solving quadratic inequalities.

When solving quadratic inequalities, you always have to remember that if you are dividing by a negative, you have to flip the inequality sign.

Step 1: Find the roots of a quadratic inequality:

Step 2: Insert the roots into a numbe line:

Then you can pick 3 numbers from the 3 sections on the number line and insert them into the original equation.

I picked 0 becuase it is quick and easy:

I got a positive number so, any number below 2 is positive.

Then I did the same with the number 3:

I got a negative number, that means that all numbers between 2 and 7 would result in a negative number.

Then I did the same with 10 and got a positive number, which means all numbers above 7 would result in a positive number. But the equation is asking which number could be inserted into the equation that would result in negative number. Looking back at the number line I see that all numbers beteeen 2 and 7 would result in a negative number. So the answer is 2<x<7.

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