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## Question

secondary 2 | Maths

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Not sure how to do this

lol

y² = 3 or y² = 1

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now notice that y⁴ = (y²)²

So

(y²)² - 4(y²) + 3 = 0

It is actually now in the form of a quadratic equation. You can use a substitution like u = y² if you find it difficult to visualise.

Then,

(y² - 1)(y² - 3) = 0

y² - 1 = 0 or y² - 3 = 0

y² = 1 or y² = 3

y = ± 1 or y = ± 3 (rejected as y is integer)

So y = 1 or y = -1

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