Question

How do you solve `1/5-1/20=1/x` and find any extraneous solutions?

Answer 1

`x=-15`

Explanation:

The equation is 'undefined' for `x=0`. You are mathematically 'not allowed' to divide by 0

However, the equation structure is such that the value of `x` is fixed at a value other than 0

Turn everything upside down giving

`x=5-20 =-15`