We can use some simple algebra and rewrite the equation in slope-intercept form (y = mx + b), a form of a line that is the most familiar to people.
We have y = (1/2)x + 5
Because we have second line parallel to the first line, the equation of second line is y = (1/2)x + b', where b' couul be any real number ( for instance b' = 15); then y = (1/2)x + 15;
Finally, 2y -30 = x is the equation of second line.