Which equation is not an identity? a) 0+7=7 b) 1•9=9 c) x+3=3+x d) x+1=x you so

D

Step-by-step explanation:

If you add 0 to anything, you do not have anything new when you are finished. A is an identity.

When you multiply 1 times anything, you do not get anything new. B is an identity

When you switch the order of two numbers and they are not affected by signs, then you are using the commutative property of addition. Nothing changes. C is an identity.

D is the problem child. Nothing I can think of right now will not change will you add 1 to it. If you can think of something that doesn't change when you add one to it, please put it in the comments. Otherwise, D is not an identity.