3/8+2/15+х=90 с дробями

3/8 + 2/15 + x = 90x = 90 - 3/8 - 2/15x = 90 - 45/120 - 16/120x = 90 - 61/120x = 89 целых  59/120

45/120+16/120+х=9061/120+х=90х=90-61/120х=89ц59/120