Answer:
Half of a number is 15
Step-by-step explanation:
First of all, add commas between each option so it's easier to read I had a hard time figuring out what the options were because of this.
An equation is a statement that the values of two mathematical expressions are equal. An expression is a collection of symbols that jointly express a quantity. This means there has to be an equal sign when the phrases are put into numerical form.
Twice as much as a number: 2X
12 less than a number: X - 12
Half of a number is 15: X/2 = 15
The difference of 20 and a number: 20 - X
As you can see, only one of these phrases is an equation by definition, and that is X/2 = 15, or half of a number is 15. That's because it's the only one that values two expressions as equal.
