Odpowiedź :
√7 - 3 √7 + 3 (√7-3)* (√7-3) (√7+3) (√7+3)
⁻⁻⁻⁻⁻⁻ - ⁻⁻⁻⁻⁻⁻⁻ = -------------- - ------------- = √7 + 3 √7 - 3 (√7+3)(√7-3) (√7-3)(√7+3)
7-3√7-3√7+9 7+3√7+3√7+9 7-3√7-3√7+9 - (7+3√7+3√7+9)
-------------- - ------------- = --------------------------------- =
-2 -2 -2
16-6√7 - 16 -6√7 12√7
------------------- = ------- = -6√7
-2 -2
⁻⁻⁻⁻⁻⁻ - ⁻⁻⁻⁻⁻⁻⁻ = -------------- - ------------- = √7 + 3 √7 - 3 (√7+3)(√7-3) (√7-3)(√7+3)
7-3√7-3√7+9 7+3√7+3√7+9 7-3√7-3√7+9 - (7+3√7+3√7+9)
-------------- - ------------- = --------------------------------- =
-2 -2 -2
16-6√7 - 16 -6√7 12√7
------------------- = ------- = -6√7
-2 -2