<span>Решение </span><span>21*(15+5)+19*(15+3)+17*(15+1)=57*15+21*5+19*3+17=57*15+(15+6)*5+(15+4)*3+15+2= </span><span>=66*15+6*5+4*3+2=68*15+14 </span><span>Остаток 14</span>