The number of permutations of the 4 different letters, taken two at a time, is given by:
Associative Property of Addition hope this helps
Answer:

Step-by-step explanation:
We are to determine which of these expressions are equivalent to: 




Therefore, the two equivalent expressions are:

Answer:
x = all real numbers because this equation is an identity
Step-by-step explanation:
9 (1/3) = 9*1/3 = 3
3 + 8x = 4(2x + 3/4)
3 + 8x = 8x + 3
x = all real numbers because this equation is an identity