Find the value of λ so that the lines and are perpendicular to each other.

We know that, any line passing through a (x₁, y₁, z₁) and having direction ratios a, b and c has equation

Given, equations of lines are

and

Rewriting the above equations in standard form,

and

Hence, direction ratios of two lines are and

Since, two lines are perpendicular, dot product of these two lines will be equal to zero

⇒ λ = 7