Angle a and b are supplementary angles which means that when added they equal 180. so we must set our equation equal to 180. 8x+74+2x+56=180 which simplifies to 10x+130=180 then subtract 130 from both sides. 10x=50 x=5
So we plug in 5 to find the measure of b. 2(5)+56=b 10+56=b 66=b the measure of angle b is 66 degrees
