Answer:
If y varies inversely as x, then we write it as:
y = k/x
where k is some constant.
If we multiply both sides of this equation by x we get an equation for k:
k = x*y
We are given that y=4 when x=7, therefore:
k = 7*4 = 28
Put this back into our original equation to get:
y = 28/x