Решим каждое уравнение по порядку:
1) $$x + 3 = -9x$$
Перенесем $$-9x$$ влево, а 3 вправо:
$$x + 9x = -3$$
$$10x = -3$$
$$x = \frac{-3}{10}$$
$$x = -0.3$$
2) $$-3x - 9 = 2x$$
Перенесем $$-3x$$ вправо, а 9 влево:
$$-9 = 2x + 3x$$
$$-9 = 5x$$
$$x = \frac{-9}{5}$$
$$x = -1.8$$
3) $$6x + 1 = -4x$$
Перенесем $$-4x$$ влево, а 1 вправо:
$$6x + 4x = -1$$
$$10x = -1$$
$$x = \frac{-1}{10}$$
$$x = -0.1$$
4) $$-2x - 4 = 3x$$
Перенесем $$-2x$$ вправо, а $$-4$$ влево:
$$-4 = 3x + 2x$$
$$-4 = 5x$$
$$x = \frac{-4}{5}$$
$$x = -0.8$$
5) $$3x + 3 = 5x$$
Перенесем $$3x$$ вправо, а $$3$$ влево:
$$3 = 5x - 3x$$
$$3 = 2x$$
$$x = \frac{3}{2}$$
$$x = 1.5$$
6) $$-8x - 3 = -6x$$
Перенесем $$-8x$$ вправо, а $$-3$$ влево:
$$-3 = -6x + 8x$$
$$-3 = 2x$$
$$x = \frac{-3}{2}$$
$$x = -1.5$$
7) $$7 + 8x = -2x - 5$$
Перенесем $$8x$$ вправо, а $$-5$$ влево:
$$7 + 5 = -2x - 8x$$
$$12 = -10x$$
$$x = \frac{12}{-10}$$
$$x = -1.2$$
8) $$-5 + 9x = 10x + 4$$
Перенесем $$9x$$ вправо, а 4 влево:
$$-5 - 4 = 10x - 9x$$
$$-9 = x$$
$$x = -9$$
9) $$1 - 10x = -5x + 10$$
Перенесем $$-10x$$ вправо, а $$10$$ влево:
$$1 - 10 = -5x + 10x$$
$$-9 = 5x$$
$$x = \frac{-9}{5}$$
$$x = -1.8$$
10) $$-4 - 6x = 4x - 3$$
Перенесем $$-6x$$ вправо, а $$-3$$ влево:
$$-4 + 3 = 4x + 6x$$
$$-1 = 10x$$
$$x = \frac{-1}{10}$$
$$x = -0.1$$
11) $$2 + 3x = -7x - 5$$
Перенесем $$3x$$ вправо, а $$-5$$ влево:
$$2 + 5 = -7x - 3x$$
$$7 = -10x$$
$$x = \frac{7}{-10}$$
$$x = -0.7$$
12) $$-1 - 3x = 2x + 1$$
Перенесем $$-3x$$ вправо, а 1 влево:
$$-1 - 1 = 2x + 3x$$
$$-2 = 5x$$
$$x = \frac{-2}{5}$$
$$x = -0.4$$
13) $$4(x - 8) = -5$$
$$4x - 32 = -5$$
$$4x = -5 + 32$$
$$4x = 27$$
$$x = \frac{27}{4}$$
$$x = 6.75$$
14) $$10(x - 9) = 7$$
$$10x - 90 = 7$$
$$10x = 7 + 90$$
$$10x = 97$$
$$x = \frac{97}{10}$$
$$x = 9.7$$
15) $$5(x + 9) = -8$$
$$5x + 45 = -8$$
$$5x = -8 - 45$$
$$5x = -53$$
$$x = \frac{-53}{5}$$
$$x = -10.6$$
16) $$4(x + 1) = 9$$
$$4x + 4 = 9$$
$$4x = 9 - 4$$
$$4x = 5$$
$$x = \frac{5}{4}$$
$$x = 1.25$$
17) $$10(x + 2) = -7$$
$$10x + 20 = -7$$
$$10x = -7 - 20$$
$$10x = -27$$
$$x = \frac{-27}{10}$$
$$x = -2.7$$
18) $$5(x - 6) = 2$$
$$5x - 30 = 2$$
$$5x = 2 + 30$$
$$5x = 32$$
$$x = \frac{32}{5}$$
$$x = 6.4$$
**Ответы:**
1) $$x = -0.3$$
2) $$x = -1.8$$
3) $$x = -0.1$$
4) $$x = -0.8$$
5) $$x = 1.5$$
6) $$x = -1.5$$
7) $$x = -1.2$$
8) $$x = -9$$
9) $$x = -1.8$$
10) $$x = -0.1$$
11) $$x = -0.7$$
12) $$x = -0.4$$
13) $$x = 6.75$$
14) $$x = 9.7$$
15) $$x = -10.6$$
16) $$x = 1.25$$
17) $$x = -2.7$$
18) $$x = 6.4