Substitution method
Substitution usually refers to the method of elimination in math, mainly used to solve systems of two linear equations, and the core idea is to turn a "two-variable" problem into a "one-variable" one to solve it.
Substitution usually refers to the method of elimination in math, mainly used to solve systems of two linear equations, and the core idea is to turn a "two-variable" problem into a "one-variable" one to solve it.
Everything is a system, and every system contains systerms.