## Geometry: Common Core (15th Edition)

The single hash marks mean the segments are congruent, so the measures are equal. $3m+5=4m-10$ subtract 3m from each side $3m+5-3m=4m-10-3m$ combine like terms $5=m-10$ add 10 to each side $5+10=m-10+10$ simplify $15=m$