Answer:
168 degrees
Step-by-step explanation: first you would do (2x-3)+8x so you would have 10x-3 and that equals 180 degrees since its a straight angle. so you would do 10x-3=180 divide by 10, x-3=18 and add 3 so x=21 then since 2 is 8x you would multiply 8 by 21 which is 168.