The equation of the first line is given as,
The slope of line ax+by+c=0 is given as,
The slope of the above line is calculated as,
Equation of the second line is given as,
The equation of the second line is calculated as,
From equations (1) and (2),
The slope of line 1 = Slope of line 2
As the slope of the lines is equal therefore the lines are parallel to each other.