Can a system of two linear rules in two unknowns have exactly two solutions?
AYes, when both lines are drawn very steeply
BYes, when the two lines cross near the axes
CYes, when both rules hold the same unknowns
DNo, two straight lines cannot cross twice
Answer & Solution
Correct answer: D. No, two straight lines cannot cross twice
1. Each rule draws a straight line, and a solution is a point shared by both lines.
2. Two straight lines that meet at one point then move apart forever, so they cannot meet again.
3. If they do share a second point, they must lie on top of each other and share every point.
4. That leaves only three possibilities: one solution, none at all, or infinitely many.
5. Exactly two is not among them, so the answer is no, option D.
6. Steepness and the position of the crossing change where the lines meet, not how many times, ruling out options A and B.
7. Option C describes every system in two unknowns, so it cannot single out a special case.
_Source: OpenStax College Algebra (CC BY 4.0), Ch 7 "Systems of Equations and Inequalities", section 7.1 Systems of Linear Equations: Two Variables_
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