Given whole numbers $$A$$ and $$B$$, the operator $$*$$ is defined as $$A*B=(A\times B)+(A+B)$$.  For example, $$5*2=(5\times2)+(5+2)=10+7=17$$.  Find the value of $$a$$ if $$a*a=399$$. 
Overseas Competition->Knowledge Point->Calculation Modules->Operations with New Definition->Finding Unknowns Using the Given Operations