Mathematics for IGCSE & O level - Equations (Section 7 - No. 28)
In solving simultaneous equations using substitution, which statement is typically NOT true?
You solve one equation for a variable.
You substitute the expression for that variable into the other equation.
You combine like terms.
You substitute the values for both variables from the start
Explication
You never start by substituting the value for both variables at the start in substitution.