Question

*EXTRA PTS* find the value

Answer 1

Answer:
13) 4
14) 7
15) 8
How?
21x+6 = 90 by the alternate exterior angles rule so solve and get 4

11x-2=75 by the Corresponding exteriors angles rule so solve and you get 7

8x-4=60 by the vertical angle rule solve and you get 8

Hope this helps :D