Question

a method of solving a system of equations that involves replacing a variable with a number or another expression is called substitution elimination system of equations

Explanation:

To solve a system of equations, the substitution method specifically involves replacing a variable with a number or another expression (from one equation) into the other equation. Elimination involves eliminating a variable by adding or subtracting equations, and "system of equations" is the set of equations, not a solving method. So the correct term is substitution.

Answer:

substitution