Question

872 Решите уравнения: х+ 9
х+1
1 +
+
3
1)
7
5x - 2
2) 1 -
6
3х + 4 x-7 2(2x + 3)
3
5 2
5
97x – 3 9 – 4x
7-х
2
3
2
x - 5
9​

Answer 1

Пошаговое объяснение:

№872

1)

$\frac{x + 9}{7} = 1 + \frac{x + 1}{ 3} \\ 3(x + 9) = 21 + 7(x + 1) \\ 3x + 27 = 21 + 7x + 7 \\ 3x - 7x = 28 - 27 \\ - 4x = 1 \\ x = - \frac{1}{4 } \\ x = - 0.25$

2)

$1 - \frac{5x - 2}{6} = \frac{x - 5}{9} \\ 18 - 3(5x - 2) = 2(x - 5) \\ 18 - 15x + 6 = 2x - 10 \\ 18 - 15x + 6 = 2x - 10 \\ - 15x - 2x = - 10 - 24 \\ - 17x = - 34 \\ x = 2$

3)

$\frac{3x + 4} {5} + \frac{x - 7}{2} = \frac{2(2x + 3)}{5 } \\ 2(3x + 4) + 5(x - 7) = 2(4x + 6) \\ 6x + 8 + 5x - 35 = 8x + 12 \\ 11x - 27 = 8x + 12 \\ 11x - 8x = 12 + 27 \\ 3x = 39 \\ x = 13$

4)

$\frac{7x - 3}{2} - \frac{9 - 4x}{3} = \frac{7 - x}{2} \\ 3(7x - 3) - 2(9 - 4x) = 3(7 - x) \\ 21x - 9 - 18 + 8x = 21 - 3x \\ 29x - 27 = 21 - 3x \\ 29x + 3x = 21 + 27 \\ 32x = 48 \\ x = \frac{3}{2} \\ x = 1.5$