Ответ:

Пошаговое объяснение:

1)

-x+7=6x

6x + x = 7

7x = 7

x = 1

2)2( 7+9x)  = 14 + 18x

3)

10x+3(7-2x) = 13+2x

10x + 21 - 6x = 13 + 2x

4x + 21 = 13 + 2x

4x - 2x = 13 - 21

2x = -8

x = -8 : 2

x = -4

4)

0.6x + 100 = 0.9x + 1

0,9x - 0,6x = 100 - 1

0,3x = 99

x = 99 : 0,3

x = 330