Question

X^2-81 y^2-4a+4 36x^4y^2-169c^2 (x+1)^2-(x-1)^2

Answer 1

1) (x-9)(x+9)

2)(y-2)^2

3)(6x^2y^2-13c)(6x^2y^2+13c)

4)4x

Answer 2

It seems like you've provided a collection of mathematical expressions, but you haven't specified what you'd like to do with them or what kind of information you're seeking. These expressions appear to be quadratic equations and polynomial expressions. Please provide more context or a specific question you'd like to ask about these expressions, and I'll be happy to help.