UPSC NDA Math Model Paper 3

Given lines are 3x + 4y = 9 and 6x + 8y = 18
To Find: Distance between the lines
6x + 8y = 18
⇒ 6x + 8y - 18 = 0
Take 2 common from above equation, we get
⇒ 3x + 4y - 9 = 0 .... (1)
And 3x + 4y - 9 = 0 .... (2)
Equation 1 and 2 are parallel to each other.
∴ The distance between the lines =

|−9−(−9)|

√32+42

=0