Systems of Linear Equations and Inequalities

9000019906

Level: 
B
Consider a linear system of four equations with four unknowns. The rank of the coefficient matrix \(A\) is \(\mathop{\mathrm{rank}}(A) = 3\). The rank of the augmented matrix \(A'\) is \(\mathop{\mathrm{rank}}(A') = 4\). Identify a true statement on this system.
The system does not have any solution.
The system has infinitely many solutions.
The system has a unique solution.
It is not possible to draw any conclusion from this information.

9000019907

Level: 
B
The augmented matrix of a system of three equations with three unknowns is row equivalent with the following matrix \(A'\). Find the solution of the system. \[ A' = \left(\begin{array}{ccc|c} 1 & 2 & 4 & 0\\ 0 & 2 & 7 & 7\\ 0 & 0 & 7 & 35 \end{array}\right) \]
\([8;-14;5]\)
\([-62;21;5]\)
\([8;14;-5]\)
\([-22;-21;5]\)

9000007206

Level: 
A
Consider the linear system: \[ \begin{aligned}2x - 3y - 12& = 0,& \\\text{???}\quad & = 0. \\ \end{aligned} \] In the following list, identify the missing second equation if you know that the system does not have a solution.
\(- 6x + 9y - 9 = 0\)
\(2x + 3y - 6 = 0\)
\(- 4x + 6y + 24 = 0\)
\(x + 2y - 12 = 0\)