Who's good in MATH?

[__d_a_v_i_d__]

basically the answer is worth 50 pts for my class. which is alot... so here's the question...

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if a=b, then/proves 2=1


a = b
-b   -b
a-b = b-b
a-1 = 0  
(a-b)+(a-b) = 0+(a-b)	
2(a-b) = (a-b) 
 _____	 _____ 
(a-b)	  (a-b)
2 = 1

the underscores is the overthen/dividing.

so i told him that from the beginning it was wrong, if a=b, then a should = to 1 and b should = 1. or a=2 n b=2.

he said that's obvious, we know 2 cant = 1.

he said that one step is illegal, not allowed in the rules.

he wouldnt even tell us the method or formula or w.e he was using...

so yea. im completely lost ..

[dumontdude10]

lol im good in math but im lost whats the original question

[R_Mac_1]

Not really sure what you're asking.

[Sampsonite]

lol im good in math but im lost whats the original question

Same here...... That makes no sense

[__d_a_v_i_d__]

original question: "which step is illegal, not allowed?"

im lost aswell.. lol

[R_Mac_1]

I think it's

2(a-B )/(a-B ) = (a-B )/(a-B )

Because if a=b, then a-b = 0

You can't divide by zero

Edited January 13, 2010 by R_Mac_1

[glpg80]

I think it's

2(a-B )/(a-B ) = (a-B )/(a-B )

Because if a=b, then a-b = 0

You can't divide by zero

yeah this is correct, same thing i got out of it anyway. b/c if you do it properly you get to a step where its a-b=0 in the algebra which would make the statement 1=0 which is common sense based - not true.

so its a derivative question 2*1 = 1, where the 1's come from

(2-1)=1

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(2-1)=1

which equals 1/1=1. and we all know 2*(1/1)=2, and 1*(1/1) = 1

Edited January 13, 2010 by glpg80

[Baydestrian]

agreed

[slugdub]

I think it's

2(a-B )/(a-B ) = (a-B )/(a-B )

Because if a=b, then a-b = 0

You can't divide by zero

This is where I got too... the rest seemed pretty much worthless info.. but is the answer ever this simple?

[rusty959]

http://en.wikipedia.org/wiki/Mathematical_fallacy

Check under division by 0