how do you do this

Question

suppose that x and y vary inversely and x=1 when y-5. write a function that models the inverse variation. graph the function and find y when x=20

Answer 1

When a function varies inversely, you want to use an equation like y = k/x .

 

Substitute in x = 1 and y = 5.  

 

Solve for k.

 

Rewrite the equation, but this time use the answer you got for k in place of k.

 

Substitute 20 in for x.

 

Solve for k.

 

 

Note: 

Variesinversely means divide...use k/x.   

 

Varies directly means multiply...use kx.