Respuesta :

a triangles degrees add up to 180.
well first 180-138 for angle u which is 42

then do 42+(6y-2)+(8y+14)=180

solve for y.

42+(6y-2)+(8y+14)=180

42+6y-2+8y+14=180
54+14y=180
-54            -54
14y=126
/14      /14
y=9