Decide What Number Must Be Added to the Binomial to Make

Multiple Choice

Decide what number must be added to the binomial to make a perfect square trinomial.
- $$x ^ { 2 } + \frac { 4 } { 5 } x$$

A) $\frac { 4 } { 25 }$
B) $\frac { 16 } { 25 }$
C) $\frac { 1 } { 5 }$
D) $\frac { 8 } { 25 }$