Решите уравнение: 1) 8x = 24;

Привет! Давай решим эти уравнения: 1) $8x = 24$ $x = 24 / 8$ $x = 3$ 2) $-7k + 49 = -14k$ $-7k + 14k = -49$ $7k = -49$ $k = -7$ 3) $54 = 9n - 9$ $9n = 54 + 9$ $9n = 63$ $n = 7$ 4) $9x + 15 = 4x + 30$ $9x - 4x = 30 - 15$ $5x = 15$ $x = 3$ 5) $-z - 2,8 = -0,3z$ $-z + 0,3z = 2,8$ $-0,7z = 2,8$ $z = -4$ 6) $-9(x - 6) = 78 - 4x$ $-9x + 54 = 78 - 4x$ $-9x + 4x = 78 - 54$ $-5x = 24$ $x = -4,8$ 7) $2(7x - 3) - 5(3x + 2) = 7x - 8$ $14x - 6 - 15x - 10 = 7x - 8$ $-x - 16 = 7x - 8$ $-x - 7x = -8 + 16$ $-8x = 8$ $x = -1$ 8) $-3(4x - 1) + 13 = 5(6 - x)$ $-12x + 3 + 13 = 30 - 5x$ $-12x + 16 = 30 - 5x$ $-12x + 5x = 30 - 16$ $-7x = 14$ $x = -2$ 9) $\frac{7}{10}(\frac{5}{7}x - \frac{3}{14}) = 3x + 4\frac{3}{10}$ $\frac{7}{10} \cdot \frac{5}{7}x - \frac{7}{10} \cdot \frac{3}{14} = 3x + \frac{43}{10}$ $\frac{1}{2}x - \frac{3}{20} = 3x + \frac{43}{10}$ Умножим всё на 20, чтобы убрать знаменатели: $10x - 3 = 60x + 86$ $10x - 60x = 86 + 3$ $-50x = 89$ $x = -1,78$ 10) $9(4x - 7) - (8 - 7x) \cdot 5 = 39$ $36x - 63 - (40 - 35x) = 39$ $36x - 63 - 40 + 35x = 39$ $71x - 103 = 39$ $71x = 142$ $x = 2$