How to solve the equation 2X-4 [X-15] = 18?

How to solve the equation 2X-4 [X-15] = 18?

2X-4(X-15)=18
To get rid of brackets: 2x-4x + 60 = 18
Transfer merger: - 2x = 18-60
-2x=-42
When the coefficient is changed to 1, x = 21