Решите уравнение: 1) 7(x + 2) = -14;

### Решение номера 1422 1) $7(x + 2) = -14$ $7x + 14 = -14$ $7x = -28$ $x = -4$ 2) $8y = 2(5 - y)$ $8y = 10 - 2y$ $10y = 10$ $y = 1$ 3) $2(3x - 4) = 4(x - 3)$ $6x - 8 = 4x - 12$ $2x = -4$ $x = -2$ 4) $7(x + 3) - 2(x - 5) = 8$ $7x + 21 - 2x + 10 = 8$ $5x + 31 = 8$ $5x = -23$ $x = -4,6$ 5) $5 + 3(2y - 1) = 2(y - 3)$ $5 + 6y - 3 = 2y - 6$ $6y + 2 = 2y - 6$ $4y = -8$ $y = -2$ 6) $-x - 5,2 = 12 - 2(x + 0,6) - 10$ $-x - 5,2 = 12 - 2x - 1,2 - 10$ $-x - 5,2 = 0,8 - 2x$ $x = 6$ ### Решение номера 1423 1) $0,6(0,5x + \frac{2}{3}) = 2,25 + 5,3x$ $0,3x + 0,4 = 2,25 + 5,3x$ $-5x = 1,85$ $x = -0,37$ 2) $5 - y = 8 - \frac{1}{3}(4,5y - 5)$ $5 - y = 8 - 1,5y + \frac{5}{3}$ $0,5y = 3 + \frac{5}{3} = \frac{14}{3}$ $y = \frac{28}{3} = 9 \frac{1}{3}$ 3) $\frac{1}{2}(x - 4) + 6x = 5 - 1 \frac{1}{2} x$ $0,5x - 2 + 6x = 5 - 1,5x$ $6,5x + 1,5x = 7$ $8x = 7$ $x = 0,875$ 4) $3,2(1 - 2y) = 0,7(3y - 1,5)$ $3,2 - 6,4y = 2,1y - 1,05$ $4,25 = 8,5y$ $y = 0,5$ 5) $\frac{5}{12}(z - 3) = \frac{1}{6}(2z - 7) + 2$ Умножим на 12: $5(z - 3) = 2(2z - 7) + 24$ $5z - 15 = 4z - 14 + 24$ $z = 25$ 6) $\frac{5}{8}(x - 2) = \frac{2}{3}(x + 2) - (3 - x)$ Умножим на 24: $15(x - 2) = 16(x + 2) - 24(3 - x)$ $15x - 30 = 16x + 32 - 72 + 24x$ $15x - 30 = 40x - 40$ $10 = 25x$ $x = 0,4$ 7) $\frac{1}{6}y - (0,5 + \frac{8}{9}y) = \frac{1}{9}y - (\frac{1}{3} + y)$ Умножим на 18: $3y - (9 + 16y) = 2y - (6 + 18y)$ $3y - 9 - 16y = 2y - 6 - 18y$ $-13y - 9 = -16y - 6$ $3y = 3$ $y = 1$ 8) $\frac{3}{5}(3 - 2z) = \frac{2}{5}(9 - z) - 0,3(z - 9)$ $0,6(3 - 2z) = 0,4(9 - z) + 0,3(9 - z)$ $1,8 - 1,2z = 0,7(9 - z)$ $1,8 - 1,2z = 6,3 - 0,7z$ $-4,5 = 0,5z$ $z = -9$