Where two lines cross.
Finding the single point (x, y) that works for two different equations.
Used in economics to find where Supply meets Demand.
Substitution or Elimination: pick your weapon.
Plain English: A system asks: 'When will these two things be equal?' It's solving two puzzles at once to find the one answer that fits both.
Real-world example: Comparing two cell phone plans to see which is cheaper for your usage.
Finding X but forgetting to plug it back in to find Y.