Let the equation of the plane through (-1 , -2 , -1) be a(x + 1) + b (y + z) + c (z + 1) = 0 As the normal to the plane is perpnedicular to the given lines 3a + b + 2c = 0 a + 2b + 3c = 0 ⇒
a
−1
=
b
−7
=
c
5
⇒ Equation of the plane is x + 7y - 5z + 10 = 0 Distance of (1, 1, 1) from the plane i |