Answer:
y = x ±√(x²+1)
Step-by-step explanation:
Rewrite to standard quadratic form, then use the quadratic formula.
... y² -2xy -1 = 0
... a=1, b=-2x, c=-1, so the quadratic formula
... y = (-b ±√(b²-4ac))/(2a)
can be filled in as ...
... y = -(-2x) ±√((-2x)² -4(1)(-1)))/2(1))
... y = x ±√(x² +1)
For any given value of x, there are two possible values of y. This is <em>not</em> a function.
