For each of the quadratic equations below, convert them into the standard form $$ax^2+bx+c=0$$ and determine the value of '$$b^2-4ac$$. Comment on the nature of roots from the value of '$$b^2-4ac$$
(i) $$5x^2=6x-7$$
(ii) $$4x^2+16=-16x$$
(iii) $$2x^2+6x+3=0$$
What is the value of $${i^i}$$
Where $$i = \sqrt { - 1} $$