Divide both sides by \({1}^{\imath }\).
\[\frac{sum-1}{{1}^{\imath }}=nfty\]
Simplify \(\frac{sum-1}{{1}^{\imath }}\) to \((sum-1)\).
\[sum-1=nfty\]
Divide both sides by \(n\).
\[\frac{sum-1}{n}=fty\]
Divide both sides by \(f\).
\[\frac{\frac{sum-1}{n}}{f}=ty\]
Simplify \(\frac{\frac{sum-1}{n}}{f}\) to \(\frac{sum-1}{nf}\).
\[\frac{sum-1}{nf}=ty\]
Divide both sides by \(t\).
\[\frac{\frac{sum-1}{nf}}{t}=y\]
Simplify \(\frac{\frac{sum-1}{nf}}{t}\) to \(\frac{sum-1}{nft}\).
\[\frac{sum-1}{nft}=y\]
Switch sides.
\[y=\frac{sum-1}{nft}\]
y=(s*u*m-1)/(n*f*t)
