Find ( Fg )(X) $f ( x ) = \sqrt { 3 x } \quad g ( x ) = \sqrt { 5 x + 7 }$

Multiple Choice

Find ( fg ) (x) . $f ( x ) = \sqrt { 3 x } \quad g ( x ) = \sqrt { 5 x + 7 }$

A) $( f g ) ( x ) = \sqrt { 8 x + 7 }$
B) $( f g ) ( x ) = \sqrt { 15 x ^ { 2 } + 7 }$
C) $( f g ) ( x ) = \sqrt { 15 x ^ { 2 } + 21 x }$
D) $( f g ) ( x ) = x \sqrt { 15 } + \sqrt { 21 x }$
E) $( f g ) ( x ) = x \sqrt { 15 + 21 x }$