Легко: 8.6 * 0.18 - 1 действие, оно равно = 1.548
2) 4.86:5.4 = 0.9
3) 1.548 - 0.9 = 0.648
4) о.648 + 0. 452 = 1.1
4*4.5 + 25 - 3 * 4.5=18 + 25 - 13.5=56.5
4*2.7 + 25 - 3*2.7=10.8 + 25 - 8.1 = 43.9
25л - 100%
Хл - 21%
Х=(25 * 212) :100 = 21:4=5,25(л)
A² - b² = (a - b)(a + b) = 24
(a + b)²(a - b)² = (a² - b²) = 24² = 576
(a - b)² = 576/(a + b)² = 576/36 = 16
Ответ: 16