## Precalculus (6th Edition)

$(10x+7)^\circ=107^\circ$ $(7x+3)^\circ=73^\circ$
If two angles are supplementary, the sum of the two angles is a straight angle ($180^\circ$): $(10x+7)^\circ+(7x+3)^\circ=(17x+10)^\circ=180^\circ$ $x=10$ $(10x+7)^\circ=107^\circ$ $(7x+3)^\circ=73^\circ$