t² – 15
= t² – (√15)²
= (t + √15)(t – √15)
The value of t² – 15 is zero if t + √15 = 0 or t – √15 = 0.
⇒ x = – √15 or x = √15.
Therefore, the zeroes of t² – 15 are – √15 and √15.
Now, Sum of zeroes = -√15 + √15 = 0 = -(0)/1 = -(Cofficient of t)/(Cofficient of t²)
Product of zeroes = (-√15) x √15 = -15 = -15/1 (Constant term)/(Cofticient of t²)

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