Question

2z + 2z - 4 = 4z - 4

Explanation:

Step1: Combine like - terms on the left - hand side

$2z+2z - 4=(2 + 2)z-4=4z - 4$
The left - hand side $4z - 4$ is equal to the right - hand side $4z - 4$. This equation is an identity, which means it is true for all real values of $z$.

Answer:

The solution is all real numbers.