If lines are Ax + By + C1 = 0 and Ax + By + C2 = 0, then distance between parallel lines, d =

|C1−C2|

√A2+B2

(i) Here, A = 15, B = 8, C1 = – 34, C2 = 31
d =

|−34−31|

√(15)2+(8)2

=

65

17

units
(ii) The line can be re-written as lx + ly + p = 0 and lx + ly – r = 0
Here A = l, B = l, C1 = p, C2 = –r
d =

|p+r|

√(l)2+(l)2

=

p+r

l√2

units