Question 1784
{{{x^2 - 4x + 5 = 0}}}

using the formula...

{{{x = (4 +- sqrt(16-20))/2}}}
{{{x = (4 +- sqrt(-4))/(2)}}}
{{{x = (4 +- 2i)/(2)}}} where -4 is thought of as 4x(-1) and so sqrt of 4 is 2 and sqrt of -1 is the letter i

so we have {{{x = (4 + 2i)/2}}} and {{{x = (4 - 2i)/2}}}
this gives...

{{{x = (2 + i)}}} and {{{x = (2 - i)}}}

hope this helps
Jon

Good luck