Is the following an identity or have no solution. 2 (a-4) = 4a - (2a+4)

This equation is invalid, the left and right sides are not equal, therefore there is no solution.

You multiply everything in the parenthesis by the number outside.

In this case its 2 and - 1. the first part is 2a-8 the second part is 4a - 2a+16a

so it looks like this 2a-8=4a-2a+16a.

combine like terms and get 2a-8=18a.

Subtract the other 2a from the other side and you have 8=16a

divide each side by 16 and you have 8/16 which is one half.