If y varies inversely with x, and x = -10 when y = 60. How do you find the inverse variation equation and use it to find the value of y when x = 15?
The equation is
So by substitution we have:
Multiply both sides by
In an inverse variation, as one quantity increases, the other one decreases.
A proportion can be made into an equation by using a constant:
Use the two values given to find the value of
The equation can therefore be written as:
Now we know the exact relationship between