When the function $f ( x ) = 6 x ^ { 2 } + 2 a x$ satisfies $\int _ { 0 } ^ { 1 } f ( x ) d x = f ( 1 )$, what is the value of the constant $a$? [2 points] (1) $- 4$ (2) $- 2$ (3) 0 (4) 2 (5) 4
When the function $f ( x ) = 6 x ^ { 2 } + 2 a x$ satisfies $\int _ { 0 } ^ { 1 } f ( x ) d x = f ( 1 )$, what is the value of the constant $a$? [2 points]\\
(1) $- 4$\\
(2) $- 2$\\
(3) 0\\
(4) 2\\
(5) 4