Find the Cosine of the Angle Between the Two Planes $\sqrt { 35 }$

Multiple Choice

Find the cosine of the angle between the two planes x + y + z = 0 and x + 2y + 3z = 1.

A) 4/ $\sqrt { 35 }$
B) 6/ $\sqrt { 35 }$
C) 7/ $\sqrt { 35 }$
D) 8/ $\sqrt { 35 }$
E) 5/ $\sqrt { 42 }$
F) 6/ $\sqrt { 42 }$
G) 7/ $\sqrt { 42 }$
H) 8/ $\sqrt { 42 }$