How to find the first 3 terms of the arithmetic series

n=32
a(sub)n = -86
Sn= 224

PLEASE HELP I have no idea how to do this !

Let a(n) denote the nth term.
We are told a(32) = -86.

The sum of the first 32 terms is 224 so the mean of these is 224/32 = 7.

The mean of a(1) and a(32) is ½ ( a(1) + a(32) ) = 7
½ ( a(1) - 86 ) = 7
a(1) - 86 = 14
a(1) = 14 + 86
a(1) = 100

From a(1)=100 to a(32)=-86 is -186 and there are 32 terms (31 differences) so the difference between terms is 186/31 = -6.

So a(1) = 100, a(2) = 94, a(3) = 88.

The first three terms are 100, 94, 88.

I hope this helps.