Question 152423
It seems that 2/5xi + 3 should be changed to 2/5x + 3i.  
NOTE THAT: Two complex numbers are equal if and only if their real parts are equal and their imaginary parts are equal.
Therefore for {{{(2/5)*x+3i}}} and {{{-4-(1/4)*yi}}} to be equal, two conditions must be satisfied:
{{{(2/5)*x=-4}}}
{{{3=-(1/4)*y}}}
Solving the first equation for x, we have x=-10.
Solving the second equation for y, we have y=-12.