Question

How do you find the multiplicative inverse of 5/7?

Answer 1

It's `\frac{7}{5}`.

By definition, the inverse multiplicative of a number `x` is a number `y` such that `x \cdot y=1`. So, we have to find a number `y` such that `\frac{5}{7}\cdot y=1`, and that number is of course `\frac{7}{5}`.