# y varies inversely with x. Find the inverse variation equation if x = 12 when y = -18

• August 27th 2012, 09:04 AM
zales127
y varies inversely with x. Find the inverse variation equation if x = 12 when y = -18
Need help with this problem: y varies inversely with x. Find the inverse variation equation if x = 12 when y = -18 and what formula to use to get the correct answer. Thank you in advance
• August 27th 2012, 09:08 AM
HallsofIvy
Re: y varies inversely with x. Find the inverse variation equation if x = 12 when y =
I'm very surprised that you would be given a problem like that and not even be told what "inverse variation" means! If x and y have an "inverse variation" then $y= \frac{k}{x}$ which is the same as xy= k. Knowing that "x= 12 when y= -18" lets you calculate k.
• August 27th 2012, 09:10 AM
Wilmer
Re: y varies inversely with x. Find the inverse variation equation if x = 12 when y =