Mathematics for IGCSE & O level - Equations (Section 3 - No. 17)
When is the substitution method most effective for solving a system of equations?
When both equations are in standard form (ax + by = c).
When one equation is easily solved for one variable.
When the equations are linear.
When neither equation is easily solved for a variable.
Обяснение
Substitution works best when one equation is already solved, or easily solved, for a variable.