Question 91513
x^2/9 - y^2/81 = 1
This is a horizontal hyperbola with center (0,0).
a = 3
b = 9
Box Points: (3,9), (-3,9), (3,-9), and (-3,-9)
m = +-3
y = m(x - x1) + y1
y = 3(x - 3) + 9 and y = -3(x + 3) + 9
y = 3x and y = -3x
{{{graph(300,300,-10,10,-30,30,3x,-3x,3*sqrt(x^2 - 9),-3*sqrt(x^2 - 9))}}}