3. НОД = 2 · 3 · 7 = 42
НОК = 2² · 3² · 7² = 1764
4. - 5 < x < 7
x= - 4
5. a) a(a-3,2)(2a+4) = 0
a = 0 => a₁ = 0
a-3,2 = 0 => a₂ = 3,2
2a+4 = 0 => a₃ = -2
Ответ: {-2; 0; 3,2}
5. б) -5,4 - 3x = - 3,6
- 3x = - 3,6 + 5,4
- 3x = 1,8
x = 1,8 :(-3)
x = -0,6
Ответ: {-0,6}
5. в) |y|=16,8
y₁ = 16,8
y₂ = - 16,8
Ответ: {-16,8; 16,8}
6. 5a+6a-19a+4a = -4a
0,8x*(0,7)y = -0,56xy
7. ![-2\frac{2}{3}+ 2\frac{1}{3}*(-15\frac{3}{7}-(-4,8): \frac{4}{15} )= -2\frac{2}{3}+ 2\frac{1}{3}*(-15\frac{3}{7}-(-4,8): \frac{4}{15} )=](https://tex.z-dn.net/?f=-2%5Cfrac%7B2%7D%7B3%7D%2B%202%5Cfrac%7B1%7D%7B3%7D%2A%28-15%5Cfrac%7B3%7D%7B7%7D-%28-4%2C8%29%3A%20%5Cfrac%7B4%7D%7B15%7D%20%29%3D)
![3\frac{1}{3} 3\frac{1}{3}](https://tex.z-dn.net/?f=3%5Cfrac%7B1%7D%7B3%7D)
![1)(-4,8): \frac{4}{15} = -\frac{4,8*15}{4}=-18 1)(-4,8): \frac{4}{15} = -\frac{4,8*15}{4}=-18](https://tex.z-dn.net/?f=1%29%28-4%2C8%29%3A%20%5Cfrac%7B4%7D%7B15%7D%20%3D%20-%5Cfrac%7B4%2C8%2A15%7D%7B4%7D%3D-18)
![2)-15\frac{3}{7}-(-18)= -15\frac{3}{7}+18=2\frac{4}{7} 2)-15\frac{3}{7}-(-18)= -15\frac{3}{7}+18=2\frac{4}{7}](https://tex.z-dn.net/?f=2%29-15%5Cfrac%7B3%7D%7B7%7D-%28-18%29%3D%20-15%5Cfrac%7B3%7D%7B7%7D%2B18%3D2%5Cfrac%7B4%7D%7B7%7D)
![3)2\frac{1}{3}*2\frac{4}{7}= \frac{7}{3}*\frac{18}{7}=\frac{7*18}{3*7}=6 3)2\frac{1}{3}*2\frac{4}{7}= \frac{7}{3}*\frac{18}{7}=\frac{7*18}{3*7}=6](https://tex.z-dn.net/?f=3%292%5Cfrac%7B1%7D%7B3%7D%2A2%5Cfrac%7B4%7D%7B7%7D%3D%20%5Cfrac%7B7%7D%7B3%7D%2A%5Cfrac%7B18%7D%7B7%7D%3D%5Cfrac%7B7%2A18%7D%7B3%2A7%7D%3D6)
![4)-2\frac{2}{3}+6=3\frac{1}{3} 4)-2\frac{2}{3}+6=3\frac{1}{3}](https://tex.z-dn.net/?f=4%29-2%5Cfrac%7B2%7D%7B3%7D%2B6%3D3%5Cfrac%7B1%7D%7B3%7D)
8. 5x + 6x + 8x = 114
19x = 114
x=114 : 19
x = 6
5 · 6 = 30 первая сторона
6 · 6 = 36 вторая сторона
8 · 6 = 48 третья сторона