Answer:
The solution is 25, 36, 49
Explanation:
a = 1
b = 3
c = 5-3
= 2
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Un =

Un =

Un =

Un =

Un =

Un =

Un =

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Un = n²
U5 = 5²
= 25
U6 = 6²
= 36
U7 = 7²
= 49
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So, the next three members are 25, 36, 49