Пусть числа: (n-1), n, (n+1)
(n-1)n(n+1) = n(n² - 1) = 8(n-1 + n + n+1) = 24n
n² - 1 = 24
n² = 25
n = 5
Числа: 4; 5; 6
4² + 5² + 6² = 16 + 25 + 36 = 77
Ответ: 77
Возьмем за 100%-680.000 р
x%-850.000 р
Решаем пропорцией:
х=850000×100/680000=125%
Таким образом, 125%-100%=25%
20+х=45-4х
20+х-45+4х=0
5х-25=0
5х=25
х=5
3)
x - 7 = 14
x = 14 + 7
x = 21
4)
21 - 5x = 6
-5x = 6 - 21
-5x = -15
x=3
5)
x + x + 4 + x = 16
3x = 16 - 4
3x = 12
x = 12/3
x = 4
6)
<span>х + 5 + х + 6 = 21
</span>2x = 21 - 11
2x = 10
x = 10/2
x = 5
7)
<span>х + 2х - 5 = 40
</span>3x = 40 + 5
3x = 45
x = 45/3
x = 15
8)
0.1x = 3
x = 3/0.1
x = 3 * 10
x = 30
<span> sinx =0</span>⇒х=πп⇒х=0,х=π,х=2π