Answer:
coefficients: {-2, +9, -3}
variables: {x}
terms: {-2x^2, 9x, -3}
constant: {-3}
Explanation:
It is difficult to "label" here, so we'll list each, separated by commas.
Coefficients
Coefficients are the multiplicative factor of an expression. Depending on the expression of interest, it may consist of numbers, variables, or expressions. Here, we consider the expression of interest to be powers of x, so the coefficients are as listed. The last one (-3) is sometimes called a "constant coefficient." It multiplies x^0.
coefficients: {-2, +9, -3}
Variables
A variable is usually a letter, symbol, or sequence of letters and symbols, that stands for something else--usually an unknown quantity. Its meaning and value will depend on the context. Generic variables are usually taken from the end of the alphabet: x, y, z. Their capitalization, font, or face may give special meaning. For example bold-face capital letters may be used to represent vectors or matrices.
variables: {x}
Terms
A term is a product of coefficients and variables. Terms in a polynomial are separated by addition or subtraction symbols.
terms: {-2x^2, 9x, -3}
Constant
"Constant" usually refers to a term containing no variables. It generally refers to a value that doesn't change.
constant: {-3}