Author 
Topic 

hoshimori
New Member
USA
1 Posts 
Posted  10/02/2007 : 20:36:50

HOW ON EARTH DO YOU SOLVE LITERAL EQUATIONS??
For example:
ab=c, solve for b
Do you first divide "a" from both sides? I'm just really confused. Please give a thorough and basic summary of how to solve literal equations. 
Edited by  hoshimori on 10/02/2007 20:38:02 


the_hill1962
Advanced Member
USA
1468 Posts 

the_hill1962
Advanced Member
USA
1468 Posts 
Posted  10/03/2007 : 15:55:08

I liked how you put the numerical examples in your original post. The way that I like to introduce "solving literal equations" is by going back to a basic problem such as 2x+5=19 and then I ask the question 'could you solve for x if the equation was' 2x+a=19 ?
quote: Originally posted by David
Agreed. Everything is confusing to beginning math students! They can best learn at first, whenever possible, by seeing patterns in numerical operations, and then using exactly the same processes with literal values. In the long run, what makes the change is practice and noticing patterns [or having them pointed out.]



Inkcoder
Junior Member
USA
3 Posts 
Posted  10/04/2007 : 21:23:44

If the problem was 7a=700 how would solve it..
STEP 1: 7a=700 STEP 2: 77a=7007
Divide by 7 ON BOTH SIDES 7/7=1 So really 1*a=a. Now a=700/7, a=100.
STEP 3:a=100 BINGO, You've solved the Problem.
ab=c: Nothing different about this problem. Use the same exact steps. 
Edited by  Inkcoder on 10/04/2007 21:28:30 


the_hill1962
Advanced Member
USA
1468 Posts 
Posted  10/05/2007 : 07:38:44

Step 2 below could be a little confusing to a beginning math student (and 'technically' it is formatted wrong anyway). I have cleaned it up a little (see the second copy below this one):
quote: Originally posted by Inkcoder
If the problem was 7a=700 how would solve it..
STEP 1: 7a=700 STEP 2: 77a=7007 The above line is not formatted correctly. See the corrected copy of this post following this copy. Divide by 7 ON BOTH SIDES 7/7=1 So really 1*a=a. Now a=700/7, a=100.
STEP 3:a=100 BINGO, You've solved the Problem.
ab=c: Nothing different about this problem. Use the same exact steps.
Here it is formatted correctly (and after this copy, I have added another variable to it to make it into a "solve literally for t. Note that I added the t and went through it as if it was one of those solve literal types of problems:
If the problem was 7a=700 how would solve it..
STEP 1: 7a=700 STEP 2: 7a7=7007
Divide by 7 ON BOTH SIDES 7/7=1 So really 1*a=a. Now a=700/7, a=100.
STEP 3:a=100 BINGO, You've solved the Problem.
ab=c: Nothing different about this problem. Use the same exact steps.
Here is how it could have been a "solve literally for t" problem:
If the problem was 7at=700 how would you solve for t? STEP 1: 7at=700 STEP 2: 7a7a=7007a
Now t=700/7a
Notice the confusing end to these "solve literal" problems is that you are finished even though it does not appear to be finished (no specific numerical value). The "answer" would be just "t=700/7a" but of course, you would want to (or NEED to if your instructor requires it) simplify it to get t=100/a since 700/7=100. The answer would be "t=100/a"

Edited by  the_hill1962 on 10/05/2007 07:54:55 



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