what is wrong in it?

Question

if a=b
a*b=b*b
ab -a(sq.) = b(sq.) - a(sq.)
a(b-a) = (b+a)(b-a)
a = a+b
putting a=1
1=2

Answer 1

Same old problem . division by(a-b) is wrong that is zero.Cancellation from both sides is division

Answer 2

from the 4th to 5th step. the 5th step is wrong.
a(b-a)= (b+a)(b-a)
is equalled to
ab-aa = (a+b)x(b-a which is equalled to 0!)
and so,
ab-aa=axb-axa=0=(a+b)x0(and anything multiplied by 0 is still 0!)
and thus,
0=0,
thats where the problem lies.

Answer 3

if a=b
thn b-a=0 n u cant cancel like this
if a not=b thn u can cancel

Answer 4

a = b
a*b = b*b
ab - a^2 = b^2 - a^2
(sqrt(ab) + a)(sqrt(ab) - a) = (b + a)(b - a)
1 = 1

Answer 5

some solution or a root of equation is extraneous root. means not applicable in the equation.

Answer 6

well,
the mathematical way is to do it this way,
a(b-a) = (b+a)(b-a)
(b-a)(a-b-a)=0
(b-a)(-b)=0
b-a=0 or b=0
but b=a
therefore the general solution is
b=a.

don't ever cut both sides without considering the values of the variables!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 7

If a=b
a*b=b*b
ab-a^2=b^2-a^2
a(b-a)=(b+a)(b-a)

But, a=b, so b-a=0

a(0)=(b+a)(0)
0=0

Seems ok to me!

Answer 8

This step is wrong:

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

Because a=b, thus (b-a) is 0.

Answer 9

a(b-a) = (b+a)(b-a)
You shouldn't cancel this...