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.