The angle measurements in the diagram are represented by the following expressions.

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