Answer: -221
Explanation:
31 is smaller than 252. Therefore, since 31 MINUS x equals 252, x needs to be a negative number in order to complete the equation (recall that a negative number times a negative number equals a positive number).
Therefore, if we subtract 31 on both sides, in other words transpose, we get,
-x = 221
The coefficient of -x is -1, however it is not written as it's implied that if there is not written coefficient in from of a variable then the coefficient of the variable is 1 or -1, depending on its sign.
Therefore, dividing -1 on both sides, we get,
x = -221
Hence, the desired answer is -221.