Question
Let the complex number $z = x + iy$ be such that ${{2z - 3i} \over {2z + i}}$ is purely imaginary. If ${x} + {y^2} = 0$, then ${y^4} + {y^2} - y$ is equal to :
Let the complex number $z = x + iy$ be such that ${{2z - 3i} \over {2z + i}}$ is purely imaginary. If ${x} + {y^2} = 0$, then ${y^4} + {y^2} - y$ is equal to :