Question

Give two systems of equations that would be easier to solve by substitution than by elimination. Then give two systems that would be easier to solve with elimination. Finally, explain how you decide whether to use elimination or substitution to solve a system.

Please don't answer too complicated

Answer 1

Explanation:

if the given equations are linear, then no matter which method is used, it depends on pupils ability/habbits, but usually 'by elimination' is easier, then 'by substitution';

in the most cases the 'by substitution' can be used only (systems of non-linear equations).

Example 1. This system can be solved by any method, but 'by elimination' is shorter:

`\left \{ {{x+y=2} \atop {x-y=2}} \right.`

Example 2. This system can be solved by any method, but 'by substitution' is shorter:

`\left \{ {{2x+y=3} \atop {7x+3y=10}} \right.`