Two or more equations sharing variables. Solve all of them at once.
Three methods
- Substitution — solve one for a variable, sub into the other.
- Elimination — add or subtract equations to cancel a variable.
- Matrix — write Ax = b, multiply by A⁻¹.
Try it
x + y = 5, x − y = 1
Add: 2x = 6, x = 3. Then y = 2.