1154. Найдите корень уравнения: 1) 9(x - 1) = x + 15;

### 1154. Решение уравнений 1) $9(x - 1) = x + 15$ $9x - 9 = x + 15$ $8x = 24$ $x = 3$ 2) $(11x + 14) - (5x - 8) = 25$ $11x + 14 - 5x + 8 = 25$ $6x + 22 = 25$ $6x = 3$ $x = 0,5$ 3) $12 - 4(x - 3) = 39 - 9x$ $12 - 4x + 12 = 39 - 9x$ $24 - 4x = 39 - 9x$ $5x = 15$ $x = 3$ 4) $2(3x + 5) - 3(4x - 1) = 11,8$ $6x + 10 - 12x + 3 = 11,8$ $-6x + 13 = 11,8$ $-6x = -1,2$ $x = 0,2$ ### 1155. Решение уравнений 1) $0,8(4x + 5) = -3,2$ $3,2x + 4 = -3,2$ $3,2x = -7,2$ $x = -7,2 / 3,2 = -2,25$ 2) $-2,4(7 - 9y) = -48$ $-16,8 + 21,6y = -48$ $21,6y = -31,2$ $y = -31,2 / 21,6 = -312 / 216 = -13 / 9 \approx -1,44$ ### 1156. Решение уравнений 1) $-7(2 - 3x) = 56$ $-14 + 21x = 56$ $21x = 70$ $x = 70 / 21 = 10 / 3 = 3\frac{1}{3}$ 2) $(5 + 7a) \cdot 15 = -30$ $5 + 7a = -30 / 15$ $5 + 7a = -2$ $7a = -7$ $a = -1$ ### 1157. Решение уравнений 1) $0,3m + 2(0,2m - 0,3) = 0,8 - 0,7(m - 2)$ $0,3m + 0,4m - 0,6 = 0,8 - 0,7m + 1,4$ $0,7m - 0,6 = 2,2 - 0,7m$ $1,4m = 2,8$ $m = 2$ 2) $0,6 - (1,3x + 1) = 2,8x - 13,52$ $0,6 - 1,3x - 1 = 2,8x - 13,52$ $-0,4 - 1,3x = 2,8x - 13,52$ $13,12 = 4,1x$ $x = 13,12 / 4,1 = 3,2$ 3) $\frac{1}{8}(\frac{8}{9}y + 8) - \frac{1}{5}(\frac{5}{6}y + 1\frac{2}{3}) = 2$ $(\frac{1}{9}y + 1) - (\frac{1}{6}y + \frac{1}{5} \cdot \frac{5}{3}) = 2$ $\frac{1}{9}y + 1 - \frac{1}{6}y - \frac{1}{3} = 2$ $(\frac{2}{18} - \frac{3}{18})y = 2 - 1 + \frac{1}{3}$ $-\frac{1}{18}y = \frac{4}{3}$ $y = \frac{4}{3} \cdot (-18) = -24$