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

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