Question

19. (a + b)2 - (a? + b2) =
20. (a - b)2+(a + b)2 =
21. (a + b)2 - (a-b)2 =


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Answer 1

Answer:

19. 2ab

20. 2(a^2+b^2)

21. 4ab

Step-by-step explanation:

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