Given:
The equation of the hyperbola is:
[tex]xy=-42[/tex]
To find:
The the equation which is not an asymptote of the hyperbola.
Solution:
We have,
[tex]xy=-42[/tex]
It can be written as:
[tex]y=\dfrac{-42}{x}[/tex]
Equating denominator and 0, we get
[tex]x=0[/tex]
So, the vertical asymptotic is [tex]x=0[/tex].
The degree of numerator is 0 and the degree of denominator is 1.
Since the degree of numerator is greater that the degree of denominator, therefore the horizontal asymptote is [tex]y=0[/tex] and there is no oblique asymptote.
Therefore, [tex]y=x[/tex] is not an asymptote of the given hyperbola and the correct option is C.
