Реши уравнения 4/15+х=11/15 16/21-х=9/21 х-4/35=12/35 это дроби

4/15 + х = 11/15 х = 11/15 - 4/15 = 7/1516/21 - х = 9/21 16/21 - 9/21 = х х = 7/21 = 1/3х - 4/35 = 12/35 х = 4/35 + 12/35 х = 16/35