Hello please help I don’t know what I’m doing wrong

Explanation:
The domain of a function is the input value of any function for which the function exists.
For the function;
(f+g)(x) = 2x² + x
From the given function, we can see that the function will exist for all values of x i.e. the input variable exists on all real values.
The domain of the function in interval notation will be expressed as
(-∞, ∞)
For the function (f-g)(x) = x
Similarly for this function, the input variable exists on all real values.
The domain of the function in interval notation will be expressed as
(-∞, ∞)
For the function (fg)(x) =x^4 + x^3
Also for this function, the input variable exists on all real values.
The domain of the function in interval notation will be expressed as
(-∞, ∞)
For the function given as (f/g)(x) = 1 + 1/x
The function will not exist when x = 0. The function will be undefined at this point. The required domain of this function in interval notation will be:
[tex]D=(-\infty,0)U(0,\infty)[/tex]