Date: Tue, 2 Mar 1999 17:48:25 -0600 (CST) To: QandQ@MathCentral.uregina.ca Sender: mallorywhite@hotmail.com (Mallory White) Subject: Pre-Algebra Question
Name: Mallory White
Who is asking: Student
Question: Hi Mallory If the change you talked about bothers you then you don't need to use it. Start with
You know that you can add or subtract the same number to both sides of an inequality and still have a true statement, so you can add 4a to both sides. This gives
which becomes
Now you can subtract 14 from both sides and you see
which becomes
Now you can divide both sides by 4 and you get
which becomes
Notice that
if you read from left to right (like we do in many countries) you
read "-4.75 is less than a." If we read from right to
left (like people do in many Asian and Arabic countries) you read "a
is greater than -4.75.". Mathematics is a universal language
and we can read it either way. So you can write the answer as
-4.75 < a or a > -4.75.
and add -4 to both sides. This gives
or
Now add -7 to both sides to get
or, reading from right to left
It certainly quicker just to notice that if you multiply both sides of an equality by a negative number the direction of the inequality reverses.
Cheers, |

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