What property is illustrated by 45+19=19+45

Iwill make brain if you me correctly fill this out needs due today pls and send it back to me (click the link and you will get it)

What expression is equivalent to log3(x+4)

When you have 25 numbers, and jake picks 3 random numbers and puts them back, what is the chance bob has of picking those 3 numbers when he picks 6 random numbers (without putting them back)? explain.