# How do you write 18f^-1 using only positive exponents?

$18 {f}^{- 1} = \frac{18}{f}$
As ${a}^{- m} = \frac{1}{a} ^ m$
${f}^{- 1} = \frac{1}{{f}^{1}} = \frac{1}{f}$
Hence $18 {f}^{- 1} = 18 \times \frac{1}{f} = \frac{18}{f}$