Explanation:
let's bring both equations to the same form. i recommend the slope-intercept form as the first equation :
y = ax + b
"a" is the slope, "b" is the y-intercept (the y-value when x = 0).
y = -2x + 5
the slope is -2, and it intercepts the y-axis at y = 5.
6x + 3y = 1
3y = -6x + 1
y = -2x + 1/3
so, now we see, both lines have the same slope.
that means they are parallel.
and because they have different y-intercept values, it means they are truly parallel (different, not coinciding).