In Python, you can do it using eval() function which evaluates an expression(given by user) using BODMAS rule.
x=eval(input("Enter an expression\n"))
print(x)
In the terminal, enter expression as: -8/2*(3-6). Because, in any programming language you can not enter expression like this: -8/2(3-6). You need to put * before opening bracket.
This will result: 12.0
If you want result as 12, then use below expression:
x=int(eval(input("Enter an expression\n")))
print(x)