# Alebra Equation

• March 19th 2006, 08:54 PM
kharris82
Alebra Equation
Find an equation of variation in which y varies inversely as x and the following condition exists: 1) y=63 when x=1/7

A) y = 9/x
B) y= 2/x
C) y= 16/x
D) y = 7/x
• March 19th 2006, 11:51 PM
CaptainBlack
Quote:

Originally Posted by kharris82
Find an equation of variation in which y varies inversely as x and the following condition exists: 1) y=63 when x=1/7

A) y = 9/x
B) y= 2/x
C) y= 16/x
D) y = 7/x

$y$ varies inversely as $x$ beans that there is a constant
$k$ such that:

$
y=\frac{k}{x}
$
.

Now when $x=1/7$, $y=63$, so:

$
63=\frac{k}{1/7}=7k
$
,

hence $k=63/7=9$, and so:

$
y=\frac{9}{x}
$
,