Mathematics
(3x - 4y)2 - (3x + 4y)2 is equal to:
18x2 + 32y2
18x2 - 32y2
-48xy
48xy
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Answer
(3x - 4y)2 - (3x + 4y)2
Using the formula,
[∵(x + y)2 = x2 + 2xy + y2]
and,
[∵(x - y)2 = x2 - 2xy + y2]
= [(3x)2 - 2 (3x) (4y) + (4y)2] - [(3x)2 + 2 (3x) (4y) + (4y)2]
= [9x2 - 24xy + 16y2] - [9x2 + 24xy + 16y2]
= 9x2 - 24xy + 16y2 - 9x2 - 24xy - 16y2
= (9x2 - 9x2) + (- 24xy - 24xy) + (16y2 - 16y2)
= - 48xy
Hence, option 3 is the correct option.
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