Find the Value of X

(please don't just give me a fake answer)

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

25) 56(1) = 5b a. identity property of addition b. identity property of multiplication c. commutative property of multiplication d. commutative property of addition

What is the missing statement in step 4? ? rts ? ? vtu and ? rtu ? ? vts ? rts ? ? rvs and ? rtu ? ? stv ? vrs ? ? vru and ? usr ? ? usv ? vur ? ? vus and ? uvs ? ? sru