Two questions on chemistry and mathematics?

Question

My chemistry question:
What are polyatomic ions, how are they formed and why do they exist?

My maths question:
There has been a maths problem...
take x=1
x^=x
x^-1=x-1
(x-1)(x+1)=(x-1)
x+1=1
x=0
How can this happen?

Answer 1

Y ou divided the equation by x-1, but...

x-1 =0 and dividing by zero will always mess you up!

Answer 2

in 2nd last step u divided the 2 sides by x-1
x-1=0 and division by 0 is not valid


for chemistry part .post your question in chemistry section