Is it supposed to be equal to something, maybe "0"? You wouldn't be able to solve this without that.
The function and the first value stated for x are confusing.
Doing some research, I found that the problem is to evaluate the function

for x = - 1 and x 2.
The solution is:
1) For x = - 1

2) For x = 2
Hope this helps but I think it is A.)addition property of equality.
Answer:
x = 25°
Step-by-step explanation:
3x + 2x + x + 30° = 180°
6x + 30° = 180°
6x = 150°
x =25°
=> 3x = 25 * 3 = 75°
=> 2x = 25 * 2 = 50°
=> x + 30° = 25° + 30° = 55°