If $\frac{(2y+2z-x)}{a} = \frac{(2z+2x-y)}{b} = \frac{(2x+2y-z)}{c}$ show that: $\frac{x}{(2b+2c-a)} = \frac{y}{(2c+2a-b)} = \frac{z}{(2a+2b-c)}$