Question

Let P₁ : 2x + y - z = 3 and P₂ : x + 2y + z = 2 be two planes. Then, which of the following statement(s) is (are) TRUE? 

(A) The line of intersection of P₁ and P₂ has direction ratios 1, 2, -1 

(B) The line (3x - 4)/9 =(1 - 3y)/9 = z/3 is perpendicular to the line of intersection of P₁ and P₂ 

(C) The acute angle between P₁ and P₂ is 60° 

(D) If P₃ is the plane passing through the point (4, 2, -2) and perpendicular to the line of intersection of P₁ and P₂, then the distance of the point (2, 1, 1) from the plane P₃ is 2/√3

Answer 1

solution C,D

(A) Direction ratios of line of intersection are given by