In this question, the two given angles form a pair of linear angles, so their sum should equal 180 degrees. The expressions for the two angles are 12 x 8 12x8 and 10 + 10 x 10+10x. Set up the equation: ( 12 x 8 ) + ( 10 + 10 x ) = 180 (12x8)+(10+10x)=180