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A stupid mathematical problem!!!in a nutshell, I loaned a guy $4,000 then another day i loaned him a further $2,000. When I asked him to repay it, he said mathematically he did not owe me anything. I asked for prove, he said like this:let a = 4000, b = 2000, and c = 6,000a + b = cmultiply both sides by a + b(a + b ) * ( a + b ) = c ( a + b )a*a + a*b + b*a + b*b = c*a + c*ba*a + a*b - c*a = c*b - b*b - b*aa ( a + b - c) = -b( b + a - c )so a = - ba + b = 0thus he owes me nothing. Can you please provide a solution to this stupid mathematical problem?thanksBassam

Yes - you are right - it is a stupid maths problem.a+b-c = 0.Yet you divided both sides by (a+b-c) to get to the second last line.

a ( a + b - c) = -b( b + a - c ) can be simplified toa = - b only when (a+b-c) != 0 .

thank you guys