Hi, my friend gave me this to solve

Am I right in saying this does not compute? (a+b)(a-b)=b(a-b)Quote:

Care to help me here, this can't be right?

Given: a=b

aČ=a.b

aČ-bČ=ab-bČ

(a+b)(a-b)=b(a-b)

(a+b)=b

a+a=a

2a=a

2=1

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- January 26th 2010, 10:07 AMMukilabprove answer is wrong given a formula
Hi, my friend gave me this to solve

Quote:

Care to help me here, this can't be right?

Given: a=b

aČ=a.b

aČ-bČ=ab-bČ

(a+b)(a-b)=b(a-b)

(a+b)=b

a+a=a

2a=a

2=1

- January 26th 2010, 10:10 AMemathinstruction
the problem is the cancellation, since a=b, a-b is zero and you cant divide (cancel) by zero

- January 26th 2010, 10:12 AMMukilab