If the distance between parallel lines 3x + 4y +7 = 0 and ax + y + b = 0 is 1 , then sum of values of b is

Since lines are parallel, we have −34=−a1⇒a=34So, lines are 3x + 4y + 7 = 0 and 3x + 4y + 4b =0 Distance between lines = 1⇒|7−4b|32+42=1⇒7-4b=5 or 7-4b=-5 ⇒ b=12,3