Systems of linear equations and inequalities

2010006503

Level: 
A
Consider the linear system: \[ \begin{aligned}6x - 3y - 42& = 0,& \\\text{???}\quad & = 0. \\ \end{aligned} \] In the following list, identify the missing second equation if you know that the system does not have a solution.
\(- 2x + y +12 = 0\)
\( 2x + y +21 = 0\)
\(3x -2y -12 = 0\)
\(12x -6 y -84 = 0\)

2010006502

Level: 
A
Identify which of the following systems of equations has infinitely many solutions.
\( \begin{aligned} \frac12x-3y&=12\\ -\frac{1}3x+2y&=-8 \end{aligned} \)
\( \begin{aligned} \frac13 x-2y&=12 \\ -\frac12 x+3y&=-16 \end{aligned} \)
\( \begin{aligned} \frac12 x+2y&=12 \\ -\frac13 x-3y&=-12 \end{aligned} \)
\( \begin{aligned} \frac12 x-y&=12 \\ -\frac23 x+4y&=-8\end{aligned} \)

2010006501

Level: 
A
In \( \mathbb{R}\times\mathbb{R} \), find the solution set of the equation: \[ 3y-\frac{x+y}2=1-\frac43x \]
\( \left\{ \left[-3y+\frac65;y\right],\ y\in\mathbb{R}\right \} \)
\( \left\{ \left[-3y+\frac65;x+\frac13\right],\ x\in\mathbb{R},y\in\mathbb{R}\right \} \)
\( \left\{ \left[\frac13 y+\frac65;y\right],\ y\in\mathbb{R}\right \} \)
\( \emptyset \)

2000006804

Level: 
C
In the picture, the shaded region corresponds to the set of points that is the solution to one of the given inequalities. Which of the inequalities is it?
\[\begin{aligned} y &\leq x \\y &\geq -x \end{aligned}\]
\[\begin{aligned} y &\leq - x \\y &\geq x \end{aligned}\]
\[\begin{aligned} y &\leq x \\y &\leq -x \end{aligned}\]
\[\begin{aligned} y &\geq x \\y &\geq -x \end{aligned}\]

2000006803

Level: 
C
In the picture, the shaded region corresponds to the set of points that is the solution to one of the given inequalities. Which of the inequality is it?
\[\begin{aligned} y &\leq x+2 \\y &\geq x -2 \end{aligned}\]
\[\begin{aligned} y &\leq x-2 \\y &\geq x+2 \end{aligned}\]
\[\begin{aligned} y &\leq 2x+2 \\y &\geq 2x -2 \end{aligned}\]
\[\begin{aligned} y &\leq 2x-2 \\y &\geq 2x +2 \end{aligned}\]