Asymptotes of hyperbola

To derive the equation, find  it in terms of y. The constant term is removed.

I use a formula like the one below to solve the problem in Khan Academy https://www.khanacademy.org/math/precalculus/hyperbolic_trig_topic/hyperbolic_trig_intro/e/equation_of_a_hyperbola. 
 y1 is moved to the other side giving a  value that has an opposite sign. Please take note- this is not a fixed formula but one that I derive on my own to solve the problem faster. 

y=±(b/a)(x+x1)-y1

The fixed ones are as follows:-   y = ±(b/a)(x - h) + k for a hyperbola that opens horizontally and y = ±(a/b)(x - h) + k for a hyperbola that opens vertically. For more info, see

http://www.purplemath.com/modules/hyperbola.htm

http://laurashears.info/math122/unit4/conics/whyBoverAisAsymp.htm