Х=400*2-200
х=600
Ответ: х=600
16/3 × 9/4 ÷ 4/5 = 16/3× 9/4 = 12/1=12
12/1×5/4 = 15/1=15
<span>9/5x^2=7целых1/5
</span>9/5x^2 = 36/5
5 x ^2 * 36 = 9*5
5 x ^2 = 4 * 5
5 x ^2 = 20
x^2 = 20 / 5
x^2 = 4
x1 = 2
x2 = -2
Удачи)))
5/8х - 2 3/4 = 3/8
5/8х = 2 3/4 + 3/8
2 3/4 + 3/8 = 2 6/8 + 3/8 = 2 9/8 = 3 1/8 = 25/8
5/8х = 25/8
5х = 25
Х = 25 : 5
Х = 5
X - скорость катера км/час
6x + 12 + 8x - 16 = 164
6x + 12 + 8x = 180
14x = 168
x = 12 (км/ч)
54/12 = 4,5 часа
Ответ: 4,5 часа