Mathematics for IGCSE & O level - Equations (Section 5 - No. 42)
In the context of simultaneous equations, what does 'substitution' primarily involve?
Replacing one variable with its equivalent expression from another equation.
Eliminating both variables.
Finding the sum of the two equations.
Graphing the equations.
Explication
The essence of substitution is the replacement of a variable with its known equivalent.