Answer:
C
Step-by-step explanation:
We know every triangle equals 180 so were just going to take 180 - 42 = 138 then were going to do 138 - 67 = 71 we can check our work by doing
42 + 67+ 71 = 180. We also know 67 + 42 = 109.
Lets look at our answers;
A. 109 = 180 + x When solved it gave me; x = -71. We got a positive 71 so this is incorrect.
B. x + 42 = 67 When solved it gave me; x = 25, which is incorrect.
C. x = 180 - 109 When solved it gave me; x = 71
D. 42 + 67 - x = 180 When solved it gave me; x = - 71
Therefore the answer is C.
