Solve the Equation
- $\sqrt { 2 x ^ { 2 } + 42 } = \sqrt { x ^ { 2 } + 13 x }$

Multiple Choice

Solve the equation
- $\sqrt { 2 x ^ { 2 } + 42 } = \sqrt { x ^ { 2 } + 13 x }$

A) x=21, x=-7
B) x=6, x=7
C) x=21, x= $\frac { 13 } { 2 }$
D) x= $\frac { 13 } { 2 }$ , x=-6