How do you define a variable and write an expression for each phrase: one-third of the total of nine times a number and twenty one?

1 Answer
Jul 25, 2017

Answer:

#3x+9#

Explanation:

You don't need to "define" a variable, if that is what you mean. A variable can be any letter - #x#, #r#, #d#, etc etc. But #x# is the most common, and so I shall stick to it here.

One third of the total of states that the "nine times a number and twenty one" comes before the one-third.

Since we defined "a number" to be #x#, then nine times #x# is simplify #9x#.

The "total of" is telling us to take the sum of #9x# and #21#. It is just simplify #9x+21#

And then it is asking us to take #1/3# of that. That is just dividing #9x+21# by #3#, as #9x+21*1/3=(9x+21)div3/1#. #9x# divided by #3#
is #3x#, and #27# divided by #3# is #9#.

Therefore we get #3x+9#