Inequalities
Inequalities work the same way as normal equations. Check it out:
But there is one crucial difference: When you multiply or divide by a negative,
you must flip the inequality sign.
In that last step, we flipped the sign because we divided by a negative. There is
also a chance that an SAT problem might ask you to chart an inequality on a
number line. This is easier if you say the inequality out loud. For example, in the
above problem, our answer was “x is greater than –6.” So the number line would
look like this:
Why did we leave the circle open? Because x cannot equal –6. Let’s try a
tougher one. How about this:
x^2 ≥ 16Here, there are two possibilities:x ≥ 4 and x ≤ –4