I believe the correct answer is 0
Step-by-step explanation:
To solve this question, we use an abbreviation formula called BODMAS which is:
B = Brackets
O = Of
D = Division
M = Multiplication
A = Addition
S = Subtraction
We solve each element that is available in the order of the abbreviated letter.
1. We solve the brackets:

2. We solve the second bracket:

The equation now is 
3. We now solve addition first:

4. Now we solve the subtraction:

The answer then = 0
Answer:
Angle 1,4 and 7
Step-by-step explanation:
I know I know
I think it is 90
Hope this help you?!
The third option is the answer
Step-by-step explanation: