Mathematics
The expansion of (x - 3y)(x + 5y) is :
x2 + 2xy + 15y2
x2 + 2xy - 15y2
x2 - 2xy + 15y2
x2 - 2xy - 15y2
Expansions
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Answer
Expansion of (x - a)(x + b) = x2 - (a - b)x - ab
∴ Expansion of (x - 3y)(x + 5y) = x2 - (3y - 5y)x - 3y × 5y
= x2 - (-2y)x - 15y2
= x2 + 2xy - 15y2.
Hence, Option 2 is the correct option.
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