Lab 1 Interactive: Linear Systems

Practice the geometry and algebra of two linear equations in two unknowns. Change the coefficients, watch the lines move, classify the system, and connect the result with the ranks of the coefficient matrix and augmented matrix.

1. Build a system

The system is
\(a_1x+b_1y=c_1\)
\(a_2x+b_2y=c_2\).

Equation 1

a₁
b₁
c₁

Equation 2

a₂
b₂
c₂

2. Geometry

Blue and orange lines represent the two equations. The black point appears when there is a unique solution.

3. Rank test and RREF

The coefficient matrix and augmented matrix are

For a system \(Ax=b\), the system is consistent exactly when \(\operatorname{rank}(A)=\operatorname{rank}([A\mid b])\). For two variables, a unique solution occurs when this common rank is \(2\).

4. Student practice tasks

Task A. Use the sliders to create a system with exactly one solution. Record \(A\), \(b\), \(\operatorname{rank}(A)\), \(\operatorname{rank}([A\mid b])\), and the solution.
Task B. Use the sliders to create a system with no solution. Explain the geometry and the rank test.
Task C. Use the sliders to create a system with infinitely many solutions. Explain why the two equations define the same line.
Task D. Change only $c_2$. What changes geometrically? What changes algebraically?

5. Short-answer workspace

This space is for practice only. Students should copy their final answers into the course submission form or notebook.