I should post this 23 years ago...

Given an expression $A$ such that $A={x}^{2}+15{y}^{2}+xy+8x+y+1992$

For some $x,y\in R$ , $A$ reaches its minimum possible value of ${A}_{1}$ , which can be expressed as $a + \frac { b }{ c }$ , where $a,b,c$ are positive integers with $b,c$ coprime and $b<c$ .

Determine $a+b+c$ .

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