Question

15. Factorise : y4 - 81
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Answer 1

Step-by-step explanation:

y⁴-81

=(y²)²-(9)²

=(y²+9)(y²-9)...... a²-b²=(a+b)(a-b)

Answer 2

Answer:

y4=81

y = 81/4

y = 20.25

so the factorisation of y4=81 is 20.25