(4n+12):8=136;
4/8n+12/8=136;
1/2n+3/2=136; |*2
n+3=272;
n=272-3;
n=269;
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(4n+12):8=136; (4n+12)=136*8; (4n+12)=1088; 4n=1088-12; 4n=1076; n=1076:4; n= 269;
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(4n+12):8=136;
4 n:8+ 12:8-136=0; 0,5n+1,5-136=0; 0,5n-134,5=0; 0,5n=134,5; n=134,5:0,5; n= 269.
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Проверка; (4*269+12):8= (1076+12):8= 1088:8= 136;