Question

9. Add : x2 - y2 - 1,y2 - 1 - x2
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Answer 1

Step-by-step explanation:

9. Add :

x2 - y2 - 1,y2 - 1 - x2

= x² - y² - 1 + y² - 1 - x²

= x² - x² - y² + y² - 1 - 1

= -2