Question

(7-x)/7+x) vezes (7+x)/(7-x)

Answer 1

$\boxed{ \frac{(7-x)}{(7+x)} .\frac{(7+x)}{(7-x)} = \frac{49-x^2}{49-x^2} =1}$

Answer 2

7-x  . 7 + x   = 49 -x²   = 0
7+x    7-x        49 - x²