What counts as the solution to a system of two linear rules in two unknowns?

1. A system in two unknowns needs a value for each unknown, so a solution is a pair rather than a single number. 2. That pair has to satisfy each rule on its own, not just one of them. 3. Option B drops the word both, which is the whole point of a system. 4. So the solution is a pair of values that fits both rules at once, option D. _Source: OpenStax College Algebra (CC BY 4.0), Ch 7 "Systems of Equations and Inequalities", section 7.1 Systems of Linear Equations: Two Variables_