Answers:
(a) 4, 7, 12, 19, 28
(b) 9, 15, 21, 27, 33
(c) 3, 93, 993, 9993, 99993
(d) 1, 3, 5, 7, 9
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Step-by-step explanation
I'll show how to find a few terms from sequence (a). The same idea would apply for the other parts (b) through (d).
To get the first term, we plug in n = 1
n^2+3 = 1^2+3 = 1+3 = 4
The first term is 4.
Plug in n = 2 to get the second term
n^2+3 = 2^2+3 = 4+3 = 7
The second term is 7.
Plug in n = 3 to get the third term
n^2+3 = 3^2+3 = 9+3 = 12
The third term is 12.
And so on.