Question

y varies inversely x and y =-4 when x =7 . find the constant of variation and use it to write the equation that relates the variables

Answer 1

When y varies inversely with x, we have the follow equation:

y = kx

k = constant of variation

To find k, plugin the values for y = -4 and x = 7 and then solve for k

y = kx
-4 = k7
-4 / 7 = k7/7
-4 / 7 = k
k = -4 / 7
Now that we found k, we write the equation that relates the variables like below
$y = -\frac{4}{7}x$