4)
![\frac{12}{x+5} = - \frac{12}{5}](https://tex.z-dn.net/?f=+%5Cfrac%7B12%7D%7Bx%2B5%7D+%3D+-+%5Cfrac%7B12%7D%7B5%7D+)
![\frac{-12}{5} = -2,4](https://tex.z-dn.net/?f=+%5Cfrac%7B-12%7D%7B5%7D+%3D+-2%2C4)
![\frac{12+2,4(x+5)}{x+5} = 0](https://tex.z-dn.net/?f=%5Cfrac%7B12%2B2%2C4%28x%2B5%29%7D%7Bx%2B5%7D+%3D+0)
x≠-5
12 + 2,4x + 12 = 0
2,4x = -24
x = -10
Ответ:-10
7)
![\frac{ a^{2}-25 b^{2} }{5ab} : (\frac{a-5b}{5ab}) = \frac{ (a^{2}-25 b^{2})(5ab) }{5ab(a-5b)} = \frac{ (a-5b)(a+5b) }{(a-5b)} = a+5b](https://tex.z-dn.net/?f=+%5Cfrac%7B+a%5E%7B2%7D-25+b%5E%7B2%7D+%7D%7B5ab%7D+%3A+%28%5Cfrac%7Ba-5b%7D%7B5ab%7D%29+%3D+%5Cfrac%7B+%28a%5E%7B2%7D-25+b%5E%7B2%7D%29%285ab%29+%7D%7B5ab%28a-5b%29%7D+%3D+%5Cfrac%7B+%28a-5b%29%28a%2B5b%29+%7D%7B%28a-5b%29%7D+%3D+a%2B5b)
a = 8,0625
b = 6,1875
a+5b = 8,0625 + 5*6,1875 = 39
Ответ:39
1. x³- 1=(х-1)(х²+х+1)
2. 27 + a³=(3+а)(9-3а+а²)
3. 216 - y³=(6-у)(36+6у+у²)
4. 1/8a³ + b³=(1/2а+b)(1/4a²-1/2a+b²)
5. a⁶ - 8=(a²-2)(a⁴+2a²+4)
6. a³b³ - c³=(ab-c)(a²b²+abc+c²)
7. a³ - b¹⁵c¹⁸=(a-b⁵c⁶)(a²+ab⁵c⁶+b¹⁰c¹²
8. 125c³d³ +0,008b³=(5cd+0,2b)(25c²d²-bcd+0,04b²)
Задача 2:
(4a^2-a*b)/(a*b+14*b^2)
1. Упростим выражение вытащив за скобки "a" и "b"
(a*(4*a-b))/(b*(a+14*b))
2. Подставляем вместо a 5b и получаем
(5*b*(20*b-b))/(b*(5*b+14*b)) = 5
Ответ:
Объяснение:
0,25а^10b^6 =(0.5a^5b^3)^2
(5²)ˣ⁺¹< 6*5ˣ⁺¹ - 5
5ˣ⁺¹ = t
t² -6t +5 < 0
корни 3 и 2
-∞ 1 5 +∞
+ - + это знаки t² -6t +5
1 < t < 5
1 < 5ˣ⁺¹ < 5
5⁰ < 5ˣ⁺¹ < 5
0 < x+1 < 1
-1 < x < 0