graph the hyperbola -4x^2 + 9y^2 +8x +72y - 4= 0
- im not quite sure what to do since there are both x^2 and x as well as y^2 and y in this.

Question

anonymous · Answer

complete the square

anonymous · Answer

so get y by itself? but the hyperbolas equation has both x^2 and y^2 on one side

anonymous · Answer

You have to put it in the general equation form of the hyperbola. Start by completing the square.

anonymous · Answer

k hang on im workin on it!

anonymous · Answer

Alright, first lets group the terms a little and factor some  stuff:$$-4(x^{2} - 2x) +9(y^{2} +8y) = 4$$
now we are going to complete the square:
$$-4(x^{2} -2x +1) + 9(y^{2} +8y+16) = 4 +-4(1) + 9(16)$$
this when simplified returns:
$$-4(x-1)^{2}+9(y+4)^{2}=144$$

anonymous · Answer

http://www.wolframalpha.com/input/?i=-4x^2+%2B+9y^2+%2B8x+%2B72y+-+4%3D+0

anonymous · Answer

heromiles how do you know all these helpful websites??

anonymous · Answer

lol

anonymous · Answer

divide everything by 144:
$$-(x-1)^{2}/36  + (y+4)^{2}/16 = 1$$
that is standard form for a hyperbola

anonymous · Answer

ok thank you!!!!