Answer:
The expression 56 with a variable of -1 is not well defined. The term 56 is a constant number, and the variable of -1 is also a constant. Therefore there is nothing to evaluate.
Explanation:
If you want to evaluate the expression 56*(-1) it would give -56 as output because -1 is a scalar and multiplying with a scalar will change the sign of the constant 56 but it won't change its value.
In other words, to evaluate an expression, it needs to have a mathematical operation or function, operands, and/or variables that can be replaced with values or expressions. Without any operation, there's nothing to evaluate.