we were given this problem by my maths teacher.basically just tell me what is wrong with this :
a=b+c
a(a-c)=(b+c)(a-c)
a2-ac=ab-bc+ac-c2
a2-ab-ac=ac-bc-c2
a(a-b-c)=c(a-b-c)
a=c
come on have a go !!!
2006-09-27 08:32:46 · 15 answers · asked by Autumns_Coma 3 in Science & Mathematics ➔ Mathematics
just so u no i know the answer! i solved it in class(and got it checked) i was just wondering if any body else could see it and if u want to fell really stupid(i no i did!)then u should a 9 year old did this and he didnt know any algebra!!!
2006-09-27 08:47:37 · update #1
woo hoo i see correct answers on my screen!!!
2006-09-27 09:01:38 · update #2
The error is in the second from last line.
a(a-b-c)=c(a-b-c)
after this we divide both sides by a-b-c but since a=b+c then a-b-c=0 which means we are dividing both sides by 0. This is not allowed in maths because anything divided by 0 is infinity.
2006-09-27 08:54:22 · answer #1 · answered by brainyandy 6 · 1⤊ 0⤋
If a=c, then a-c=0 eg. 5-5=0. This means the second line is a load of crap, ie a(a-c)=(b-c)(a-c). Each side has been multiplied by zero(a-c), so each side is zero. The remaining lines from that point on are just rubbish! You can use a method like this to 'prove' that 1=2!
2006-09-27 18:21:19 · answer #2 · answered by cyberpat1957 1 · 0⤊ 0⤋
If a=c and a=b+c then some if not all the letters must equal 0
every equation ever thought of will work if all the letters used = 0
2006-09-27 22:05:37 · answer #3 · answered by "Call me Dave" 5 · 0⤊ 0⤋
if a=b+c,and a=c then b=0
2006-09-27 15:42:28 · answer #4 · answered by nirvana 3 · 1⤊ 2⤋
If a=b+c, then a-b-c=0
Well you are dividing by ZERO throughout in the step: a(a-b-c)=c(a-b-c) to get a=c
Dividing by zero is not possible and does not give zero. Hence this is the problem.
Hope I have answered your question
2006-09-27 15:59:16 · answer #5 · answered by Y L 2 · 1⤊ 0⤋
a-b-c=0, so a may not have to equal c, the maths as far as i can see is not wrong
2006-09-27 15:46:52 · answer #6 · answered by mcrat 1 · 0⤊ 1⤋
a=b+c, so a-b-c=0
Look at the second-to-last step! You can't divide by zero.
2006-09-27 16:03:59 · answer #7 · answered by عبد الله (ドラゴン) 5 · 0⤊ 0⤋
yep its true. B=0. which indeed make some of the others wrong
2006-09-27 15:45:29 · answer #8 · answered by bass player 4 · 0⤊ 2⤋
a-b-c = 0
you cannot divide by zero. i.e. you cannot cancel out (a-b-c).
thats where the error comes in.
2006-09-30 19:05:23 · answer #9 · answered by vish 2 · 0⤊ 1⤋
no... your teacher will not accept the solution, because divided by zero is invalid!
2006-09-27 17:23:11 · answer #10 · answered by Via L 2 · 0⤊ 0⤋