Step 1, multiply both sides by 30 to get15x-30 =12x-18.

Step 2: Move 12x to the left to get15x-12x = 30-18.

Step 3, add and subtract to get 3x= 12.

The best result of the fourth step is x=4.

2. 1-2x = 3x+ 1 -3。

Step 1, multiply both sides by 2 1 to get 7- 14x=9x+3-63.

Step 2: Move X to the right and move the number to the left to get 7+63-3=9x+ 14x.

The third step is to calculate 67=23x.

The result of the fourth step is x = 67 in x=23.

3，65438+65438 of 03+00 1

4、350x-250x=400