Can someone please help me thank you! will mark brainliest!

Answer:
Step-by-step explanation:
Every triangle's angles MUST add up to 180. Therefore, 43 + 43 + (6-8x) must be equal to 180. So:
43 + 43 + (6 - 8x) = 180
86 + (6 - 8x) = 180
6 - 8x = 94
-8x = 88
x = -11