## Intermediate Algebra (6th Edition)

$L=\frac{2s-na}{n}$
We are given that $s=\frac{n}{2}(a+L)$. We can use the distributive property to multiply out the terms on the right side. $s=\frac{na}{2}+\frac{nL}{2}$ Multiply all terms by 2 in order to eliminate fractions. $s\times2=\frac{na}{2}\times2+\frac{nL}{2}\times2$ $2s=na+nL$ Subtract na from both sides $2s-na=nL$ Divide both sides by n. $L=\frac{2s-na}{n}$