6.5x + x-0.5 = 7 process

6.5x + x-0.5 = 7 process

6.5x+x-0.5=7
6.5x+x=7+0.5
7.5x=7.5
x=1

-How about 4 / 5 (- 5x-30 / 4) = 7

-4 / 5 (- 5x-30 / 4) = 7
x+ 24=7
x= -17

How to do 2.5x-4.5 = 1.2 (3 + x)
Come on,

2.5x-4.5=1.2（3+x）
2.5x-4.5=3.6+1.2x
2.5x-1.2x=3.6+4.5
1.3x=8.1
x=81/13

When x satisfies (), the value of | 1.5x-0.5 | + | 2.5x-0.5 | + | 3.5x-0.5 | + | 4.5x-0.5 | + | 5.5x-0.5 | + | 6.5x-0.5 |,
Why can't the zero point short method be used to solve this problem? It's better to have a clear picture in the process of solving the problem. The answer is: 1 / 11 < = x ≤ 1 / 9, but I use the zero point segmentation method to make 1 / 8. How can I calculate it

Several cases of absolute value = 0 are x = 1 / 3,1 / 5,1 / 7,1 / 9,1 / 10,1 / 11
Draw a number axis, discuss in sections, determine the positive and negative of the absolute value, and get the result,
It is concluded that the region of minimum value is [1 / 11,1 / 9]