Choose the best definition for the following term: substitution

A letter that holds the place for some unknown value in mathematics

A process where you must look for terms that have identical variable parts and then combine their coefficients

A process where if two things are equal, one can be put in the place of the other and nothing will change

Terms that have identical variable parts

clearly it is (C) since substitute means put in the place of

The best definition for the term "substitution" is:

A process where if two things are equal, one can be put in the place of the other and nothing will change.

To arrive at this definition, we can eliminate the first option, "A letter that holds the place for some unknown value in mathematics," because while substitution in mathematics often involves replacing a letter with an unknown value, it is not the main idea behind the concept.

The second option, "A process where you must look for terms that have identical variable parts and then combine their coefficients," is more specifically related to combining like terms, rather than substitution. Substitution involves replacing one thing with another, rather than combining terms.

The third option, "A process where if two things are equal, one can be put in the place of the other and nothing will change," is the most accurate definition of substitution. In mathematics, when two expressions or equations are equal, you can substitute one expression for the other without affecting the overall equality. This concept is widely used in algebra and solving equations.

The best definition for the term "substitution" would be:

A process where if two things are equal, one can be put in the place of the other and nothing will change.