（）=7×（_ -12) If the results are the same, how to calculate them? Just fill in this way. Can you say the basic principle and its formula in the most popular language? Why do you want to calculate them like this? X=7*(X-12) X=7x-84 84=6x X = 14, please explain? I'm stupid

（）=7×（_ -12) If the results are the same, how to calculate them? Just fill in this way. Can you say the basic principle and its formula in the most popular language? Why do you want to calculate them like this? X=7*(X-12) X=7x-84 84=6x X = 14, please explain? I'm stupid

First of all: 2 * (a - b) = 2A - 2b, this is a mathematical formula, there is no reason, to remember
And: () = 7 × (_ -12) It's an equation. On both sides of the equal sign of the equation, the number on the left moves to the right (or the number on the right moves to the left) and the positive and negative will change. X = 7x-84 can be equal to x + 84 = 7x, and x-7x = - 84 is equal to - 6x = - 84, that is, 6x = 84

2 times of a number minus 4 equals to this number plus 6 times of 0.7. What is this number

This number is X
1.2x-4=x+0.7*6
1.2x-4=x+4.2
1.2x-x=4.2+4
0.2x=8.2
x=41