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- lbadeski
- Students
- Posts: 2
- Joined: Thu Aug 27, 2015 10:09 am
Combining Inequalities
I'm confused as to how/why you would combine two inequalities. Is the combined inequality actually usable? In the Algebra guide, Ch.7 Medium problems question 10, the explanation says to add the two inequalities. I don't understand what the point of it is. Thanks.
- tommywallach
- Manhattan Prep Staff
- Posts: 1917
- Joined: Thu Mar 31, 2011 11:18 am
Re: Combining Inequalities
Hey lbad,
When you're solving parallel equations, you can choose between combination (adding/subtracting the two equations) and substitution. In the case of two inequalities, you CANNOT substitute (because substitution only works if something EQUALS something else, then you can SUBSTITUTE one for the other). So oftentimes the ONLY way to work with the equations is to combine them in some way.
-t
When you're solving parallel equations, you can choose between combination (adding/subtracting the two equations) and substitution. In the case of two inequalities, you CANNOT substitute (because substitution only works if something EQUALS something else, then you can SUBSTITUTE one for the other). So oftentimes the ONLY way to work with the equations is to combine them in some way.
-t
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