WeBWorK Standalone Renderer

Which of the following expressions are equal to $1$ , $-1$ , or to neither of those? List the corresponding letter(s), separated by commas if there are more than one.

A.		$\displaystyle \frac{x-9}{9-x}$		B.		$\displaystyle \frac{x-9}{-x+9}$		C.		$\displaystyle \frac{-9+x}{x-9}$

D.		$\displaystyle \frac{-x-9}{x+9}$		E.		$\displaystyle \frac{x+9}{x-9}$		F.		$\displaystyle \frac{x + 9}{9+x}$

Equals 1:

Equals -1:

Neither:

You can earn partial credit on this problem.