Explanation: The line equates to 180, so you would put both equations (7c-7 , 6c-8) together and equal it to 180°. So, it would come out looking like this: 7c-7+6c-8=180.
You’d add 7c and 6c to get 13c, and then subtract -8 from -7 (-7-8) to get -15. The equation would now look like this. 13c-15= 180.
You’d add 15 to 180 to get 195. Then, you’d divide 195 by 13 to get 15, which would mean c=15.
