Answer:
Multiplicative Identity Property of Real Numbers.
Explanation:
The given equation is:
(x + 5) · y = x + 5
which is true for y = 1.
The property which supports this statements is Multiplicative Identity Property of Real Numbers.
According to this property if any non-zero number is multiplied to 1, the result will be the same number. Because of this 1 is known as the multiplicative identity of the Real numbers.
For any non-zero number a,
a x 1 = 1 x a = a