Answer:
Step-by-step explanation:
All these problems can be solved with two simple rules
1) intersecting lines create two pairs of opposite equal angles
2) The sum of internal angles in a triangle is 180°
the rest is simple math manipulation.
I'll set up one for you
12) 81 + (x + 5) + (6x - 11) = 180
once you have x, then the center angles are z = 6x - 11 and the other triangle is
z + (y + 14) + (4y - 18) = 180