Question 549218
What you are trying is to graph:
{{{highlight(y = sqrt(2))}}} and{{{highlight_green(y = sqrt(4))}}} and {{{y = sqrt(5)}}}blue.
In all of the cases, y is a constant and, when graphed, will result in horizontal lines passing through the constant values.
{{{graph(400,400,-5,5,-5,5,sqrt(2),sqrt(4),sqrt(5))}}}