## Geometry: Common Core (15th Edition)

The single arcs on the diagram show that $\angle BDK\cong\angle JDR$ so $3x+4=5x-10$ subtract 3x from each side $3x+4-3x=5x-10-3x$ combine like terms $4=2x-10$ add 10 to each side $4+10=2x-10+10$ $14=2x$ divide each side by 2 $14\div2=2x\div2$ $7=x$