2 1/14 - 1 2/3 X равно 521
2 1/14 - 1 2/3 х=521 1 2/3 х=521 - 2 1/14 1 2/3 х=518 13/14 х=518 13/14 : 1 2/3 х=7265/14 * 3/5 х=4359/14=311 5/14