Question

which method is most efficient for solving the system:
$x - y = 5$
$x + y = 9$
options: guess and check, elimination, graphing, substitution

Explanation:

The system of equations is \( x - y = 5 \) and \( x + y = 9 \). The elimination method is efficient here because if we add the two equations, the \( y \)-terms will cancel out (\(-y + y = 0\)), allowing us to solve for \( x \) directly. This is quicker than guess and check, graphing, or substitution for this system.

Answer:

Elimination