Find All the Real Zeros Of $f ( x ) = 4 x ^ { 3 } - 20 x ^ { 2 } + 17 x - 4$

Multiple Choice

Find all the real zeros of $f ( x ) = 4 x ^ { 3 } - 20 x ^ { 2 } + 17 x - 4$ .

A) x = $\frac { 1 } { 2 }$ , 4
B) x = $- \frac { 1 } { 2 }$ , $- \frac { 1 } { 4 }$
C) x = $\frac { 1 } { 4 }$ , -2
D) x = $\frac { 1 } { 2 }$ , $- \frac { 1 } { 4 }$
E) x = $\frac { 1 } { 2 }$ , -4