#### Answer

Fill the blanks with
$... y=2x \ \ ... \ \ y=-2x$.

#### Work Step by Step

The hyperbola $\displaystyle \frac{y^{2}}{a^{2}}-\frac{x^{2}}{b^{2}}=1$
has a vertical transverse axis and two asymptotes
$y=\displaystyle \frac{a}{b}x$ and $y=-\displaystyle \frac{a}{b}x$.
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$\displaystyle \frac{y^{2}}{2^{2}}-\frac{x^{2}}{1^{2}}=1$
$a=2, \quad b=1.$ The asymptotes are
$y=2x$ and $y=-2x$.
Fill the blanks with
$... y=2x ... y=-2x$.