a.(16-2+13=27) B.(8+2-9=11) c.(3-10+9*7=56) right

a and c are correct
b is wrong first you said B is wrong then you said its right
18 + 2 - 9 = 11

a is correct and b is incorrect.

c. is ambigupus as written. It requires more parentheses to determine if it is correct or not.
3-10+(9*7) = 56, but
(3-10+9)*7 = 14, and
3 -(10+9)*7 = -130

b.(8+2-9=11)incorrect but 18+2-9=11 is correct

I apologize for the confusion. Let's analyze the equations to determine if they are correct.

a. (16 - 2 + 13 = 27)
To verify this equation, simply perform the calculation:
16 - 2 + 13 = 14 +13 = 27
The result is 27, which matches the right side of the equation. Therefore, this equation is correct.

b. (8 + 2 - 9 = 11)
To determine if this equation is correct, let's perform the calculation:
8 + 2 - 9 = 10 - 9 = 1
The result is 1, which does not match the right side of the equation (11). Therefore, this equation is incorrect.

c. (3 - 10 + 9 * 7 = 56)
Now, let's calculate this equation to verify if it is correct:
3 - 10 + 9 * 7 = 3 - 10 + 63 = -7 + 63 = 56
The result is 56, which matches the right side of the equation. Therefore, this equation is correct.

In summary, equations a and c are indeed correct, while equation b is incorrect.