Can u explain algebra I’m a better way than my teacher Mrs Banty I don’t get it like that photo for a example

Solve the Equation
2x - 3 = 9
To solve the equation, we need to isolate the variable x. We are allowed to do any valid operation on both sides of the equation.
Start by adding 3:
2x - 3 + 3 = 9 + 3
Note we have added 3 on both sides.
Now we operate. Note the 3 and -3 will cancel out:
2x = 12
To finally isolate the x, we divide by 2:
2x / 2 = 12 / 2
Operating:
x = 6
We have solved for x. The answer is x = 6