$#min$
$2.$
$(y + 1/3) + (y + 1/9) + y + (1/27) + (y + 1/8) = 56/81$
$4y + (1/3 + 1/9 + 1/27 + 1/81) = 56/81$
$4y + (27 + 9 + 3 + 1/81) = 56/81$
$4y + 40/81 = 56/81$
$4y = 56/81 - 40/81$
$4y = 16/81$
$y=16/81 : 4$
$y=4/81$
$c)$
$1234 × 567 − 667/1234 × 566 + 567=1234$
$ =1234 × (566 + 1) - 667/1234 × 566 + 567$
$ =1234 × 566 + 1234 - 667/1234 × 566 + 567$
$ =1234 × 566 + 567/1234 × 566 + 567$
