Since A and B are opposite angles on parallel lines, we know that they sum up to 180:
[tex](8x + 74) + (2x + 56) = 180[/tex]
[tex]10x + 130 = 180[/tex]
[tex]10x = 50[/tex]
[tex]x = 5[/tex]
We can plug this into the equation for angle B to get the actual angle:
[tex]B = 2x + 56[/tex]
[tex]B = 2(5) + 56[/tex]
[tex]B = 10 + 56[/tex]
[tex]B = 66[/tex]
