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secondary 3 | A Maths
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Tricia Chew
Tricia Chew

secondary 3 chevron_right A Maths chevron_right Singapore

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Date Posted: 4 years ago
Views: 203
J
J
4 years ago
[2ⁿ+¹ (3ⁿ)]² / 36ⁿ = 9ⁿ+² / 2ⁿ

2²ⁿ+² x 3²ⁿ / (4 x 9)ⁿ = 9ⁿ+² / 2ⁿ

2²ⁿ+² x 9ⁿ / (2² x 9)ⁿ = 9ⁿ+² / 2ⁿ

2²ⁿ+² x 9ⁿ / (2²ⁿ x 9ⁿ) = 9ⁿ+² / 2ⁿ

2²ⁿ+²-²ⁿ = 9ⁿ+² / 2ⁿ

2² = 9ⁿ+² / 2ⁿ

2² x 2ⁿ = 9ⁿ+²

2ⁿ+² = 9ⁿ+²

Only possibility for n+2 = 0 for this equation to be satisfied (i.e 2^0 = 9^0 = 1)

n + 2 = 0
n = -2

Alternatively,

2ⁿ+² = 9ⁿ+²

Take ln on both sides,

ln 2ⁿ+² = ln 9ⁿ+²

(n+2)ln2 = (n+2)ln9

(n+2)(ln 2 - ln9) = 0

n + 2 = 0 since (ln2 - ln9) is negative

n = -2
J
J
4 years ago
Just swap n for x accordingly. Only the n superscript is available on my keyboard so it was used as a substitute.
Tricia Chew
Tricia Chew
4 years ago
Tks!

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Chan Zhi Zhen
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