determine if the following equation is an identity x²-y² = x²-2xy+y²
A) this is an identity because the equation is true
B) this is an identity because the equation is not true
C) this is not an identity because the equation is not true
D) this is not an identity because the equation is true
we have
x²-y² = x²-2xy+y²
Group terms
x^2-x^2=-2xy+y^2+y^2
0=-2xy+2y^2
2xy=2y^2
Simplify
x=y
so
Its not an identity because the equation is not true
the answer is the option C