Finding the Unknown

Every linear equation solves the question "what number makes this statement true?" If you know that total = rate × time and you know two of the three, you solve for the third. This single skill underlies every engineering, science, and business calculation.

Linear equations assume a constant rate — the simplest possible relationship. Real life is often nonlinear, but the habit of setting up an equation, identifying knowns and unknowns, and solving transfers to every math you will ever learn.