Question

I have a simple math question.

What is it is the letter right next to a number?

like 2x^2 x equals 4

Answer 1

Next to the number is called a variable.

Answer 2

So is it 2 times r or 2 plus r or is it 24^2?

Answer 3

All letters in equations or functions are called variables
Why called variables because there value is not known and it could be any number

Answer 4

Okay. That helps. In my question it says 2x^2 - 2z^4 and x is equal to 4 and z is equal to 2. How do solve it? do i say 24 to the power of 2?