Answer: All real numbers
Step-by-step explanation: The domain should be all real numbers, there are no restrictions
PEMDAS (order of operations rules) require that we perform operations in a certain order: anything inside parentheses first, followed by any exponentiation, followed by mult. and div., finally followed by addition and subtraction.
Thus, we must evaluate 5+8÷4-1 first, as it's inside parentheses. Focusing on the division first, we get 5+8÷4-1 = 5 + 2 - 1, or 6.
Then we have 5 - [6], which comes out to -1.
I suppose you want to know such number. Since we have a two digit number consisting of two consecutive integers, the only possible numbers are:

Since we sorted all the cases out, we simply have to check which one satisfies the requirement. For each number, we'll write four times the the sum of its digits, and add 6, hoping to get the original number.



So, the answer is 34.
Im not smart im not that sure of my answer but 23.3
Angle MNO is 90, it’s just the top right corner