Find parametric equations and symmetric equations for the line.

The line through (1,-1,1) and parallel to the line x + 2 = (1/2)y = z - 3.

My solution:

(X0, Y0, Z0) = (1,-1,1)

v = (a,b,c) = <1,1/2,1>

x -1 = (y +1)/(1/2) = z -1

x = 1 + t

y = -1 + 1/2t

z = 1 + t

The answer is:

x - 1 = (y + 1) / 2 = z - 1

x = 1 + t

y = -1 + 2t

z = 1 + t

I'm confused where the 2 came from in the y equation.