Guest Posted February 29, 2008 Report Share Posted February 29, 2008 (edited) find out what went wrong the parts indented are just explaining what happened a=b 2a=2b 2a(a-b)=2b(a-b) 2a(a-b)=2bxa-2bxb (expansion) 2a(a-b)+a=2bxa-2bxb+a (divide both sides except the "+a" by "a-b") 2a+a=2b-2b+a 2a+a=a 3a+a 3=1 Spoiler for hint: .getElementsByTagName('div')[0].style.display != '') { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = ''; this.innerText = ''; this.value = 'Hide'; } else { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = 'none'; this.innerText = ''; this.value = 'Show'; }"> Spoiler for hint: 0 Spoiler for hint] Spoiler for hint: in step 5, you divide by 0 (a-b). On one side it is canceling out the (a-b) which is 0 but on the other, it is already zero. Edited February 29, 2008 by HRAEDIUS Quote Link to comment Share on other sites More sharing options...
0 Guest Posted February 29, 2008 Report Share Posted February 29, 2008 Also, the last assumption is wrong: 3a=a (I'm pretty sure your + was a typo, since = is the logical operator for the problem and it wouldn't make sense otherwise) does not mean 3=1. a could equal 0, since 3x0=0. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted February 29, 2008 Report Share Posted February 29, 2008 a=b 2a=2b 2a(a-b)=2b(a-b) 2a(a-b)=2bxa-2bxb (expansion) 2a(a-b)+a=2bxa-2bxb+a (divide both sides except the "+a" by "a-b") 2a+a=2b-2b+a 2a+a=a 3a+a 3=1 Division by zero. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted February 29, 2008 Report Share Posted February 29, 2008 find out what went wrong the parts indented are just explaining what happened a=b 2a=2b 2a(a-b)=2b(a-b) 2a(a-b)=2bxa-2bxb (expansion) 2a(a-b)+a=2bxa-2bxb+a (divide both sides except the "+a" by "a-b") 2a+a=2b-2b+a 2a+a=a 3a+a 3=1 In step 4 you expanded the right side but not the left side... if you were to follow simple algebra rules and expand both sides of the equal sign the math would go a little different. in step 4 we would have 2axa-2axb=2bxa-2bxb now we continue with all other steps 2axa-2axb+a=2bxa-2bxb+a now we divide by the zero even though that is incorrect. We are then left with 2a-2a+a=2b-2b+a a=a 1=1 statement is true. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted February 29, 2008 Report Share Posted February 29, 2008 (edited) In step 4 you expanded the right side but not the left side... if you were to follow simple algebra rules and expand both sides of the equal sign the math would go a little different. in step 4 we would have 2axa-2axb=2bxa-2bxb now we continue with all other steps 2axa-2axb+a=2bxa-2bxb+a now we divide by the zero even though that is incorrect. We are then left with 2a-2a+a=2b-2b+a a=a 1=1 statement is true. According to the rules of algebra, expanding is legal. It is always true that a(b-c)=ab-ac. This is always true irrespective of the values of a, b, and c. Edited February 29, 2008 by brhan Quote Link to comment Share on other sites More sharing options...
0 Guest Posted February 29, 2008 Report Share Posted February 29, 2008 (edited) you got it (division by 0) Edited February 29, 2008 by HRAEDIUS Quote Link to comment Share on other sites More sharing options...
Question
Guest
find out what went wrong
the parts indented are just explaining what happened
a=b
2a=2b
2a(a-b)=2b(a-b)
2a(a-b)=2bxa-2bxb
(expansion)
2a(a-b)+a=2bxa-2bxb+a
(divide both sides except the "+a" by "a-b")
2a+a=2b-2b+a
2a+a=a
3a+a
3=1
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