If xy=0 what must be true about either x or y?
a. either x or y must equal 1
b. neither x nor y can equal 0
c. both x and y can equal 0
d. either x or y must equal 0

D. either x or y must equal 0​

Step-by-step explanation:

Its given that xy = 0

Remember that product of two numbers can be zero only if:

Both of them are zero or Either of them is zero as zero multiplied to any non-zero number will always be equal to zero. This is known as Zero Product Property.

So, if the product of x and y is equal to 0 there are two possibilities:

Note that the condition both x and y are equal to zero is not a must condition, because even if one of them is equal to zero, the entire expression will be equal to zero.

Hence, the condition which has to be true in all cases for xy = 0 is:

D. either x or y must equal 0​