Matrices and determinants

2000017413

Level: 
B
Consider the matrices \[ A=\left (\array{ 1& 0 & 0\cr -1 & 1 & 1 \cr 2& 1 & 0} \right ),~ B=\left (\array{ -1& 1 & 0\cr 0 & 1 & 1 \cr 1 &1& -1 } \right ). \] For which matrix \(X\) holds \(A \cdot B - X= B^2\)?
\( \left (\array{ -2& 1 & -1\cr 1 & -1& 0\cr 0 & 2& -1 } \right ) \)
\( \left (\array{ -2& 1 & -1\cr 1 & 1& 0\cr 0 & 2& -1 } \right ) \)
\( \left (\array{ -2& 1 & 1\cr 1 & -1& 0\cr 0 & 2& -1 } \right ) \)
\( \left (\array{ 2& 1 & -1\cr 1 & -1& 0\cr 0 & 2& -1 } \right ) \)

2000017408

Level: 
A
Find \(\frac{K \cdot (-L)}2\), if: \[ K=\left (\array{ 3& 0 & 1\cr 2 & 3 & 4 \cr 1& -1 & 1} \right ),~ L=\left (\array{ 2& 3 & 0\cr 1 & 1 & -1 \cr 2 &0& 1 } \right ) \]
\( \left (\array{ -4& -4.5 & -0.5\cr -7.5 & -4.5& -0.5\cr -1.5 & -1& -1 } \right ) \)
\( \left (\array{ -4& 4.5 & 0.5\cr -7.5 & -4.5& -0.5\cr -1.5 & -1& -1 } \right ) \)
\( \left (\array{ -4& -4.5 & -0.5\cr 7.5 & -4.5& -0.5\cr -1.5 & -1& -1 } \right ) \)
\( \left (\array{ -4& -4.5 & -0.5\cr -7.5 & 4.5& -0.5\cr -1.5 & -1& 1 } \right ) \)

2000017412

Level: 
B
For which matrices \(X\) and \(Y\) are both following equations true? \[ 3\cdot X - Y= \left (\array{ 2& -2 & -5\cr 8 & 3 & 2\cr } \right ) \] \[ X + 2 \cdot Y= \left (\array{ 3& 4& -4\cr 5 & 1 & 3\cr } \right ) \]
\(X= \left (\array{ 1& 0& -2\cr 3 & 1 & 1\cr } \right ) \), \(Y= \left (\array{ 1& 2& -1\cr 1 & 0 & 1\cr } \right ) \)
\(X= \left (\array{ 1& 0& 2\cr 3 & 1 & 1\cr } \right ) \), \(Y= \left (\array{ 1& 2& -1\cr 1 & 0 & 1\cr } \right ) \)
\(X= \left (\array{ 1& 0& -2\cr 3 & 1 & 1\cr } \right ) \), \(Y= \left (\array{ 1& 2& 1\cr 1 & 0 & 1\cr } \right ) \)
\(X= \left (\array{ 1& 0& -2\cr 3 & -1 & 1\cr } \right ) \), \(Y= \left (\array{ 1& 2& -1\cr -1 & 0 & 1\cr } \right ) \)

2000017411

Level: 
B
For which matrix \(M\) the following equality holds? \[ 2 \cdot \left (\array{ 5& -4\cr 7 & -3 \cr } \right ) - 4\cdot M = \left (\array{ 2& -20 \cr 18 & -22 \cr } \right ) \]
\( \left (\array{ 2& 3\cr -1 & 4 \cr } \right ) \)
\( \left (\array{ 2& 3\cr 1 & 4 \cr } \right ) \)
\( \left (\array{ 2& -3\cr -1 & 4 \cr } \right ) \)
\( \left (\array{ -2& 3\cr -1 & 4 \cr } \right ) \)

2000017410

Level: 
B
Find the matrix \(M\) for which the following equality is true: \[ 3 \cdot \left (\array{ 4& -1\cr 2 & 5 \cr } \right ) - 2\cdot M = \left (\array{ 14& -7 \cr 4 & 7 \cr } \right ) \]
\( \left (\array{ -1& 2\cr 1 & 4 \cr } \right ) \)
\( \left (\array{ 1& 2\cr 1 & 4 \cr } \right ) \)
\( \left (\array{ -1& 2\cr -1 & 4 \cr } \right ) \)
\( \left (\array{ -1& -2\cr 1 & 4 \cr } \right ) \)

2000017407

Level: 
A
Find \(A^2-B^2\), if: \[ A=\left (\array{ 2& 1\cr 3 & 0 \cr } \right ) , B=\left (\array{ 1& 4 \cr 2 & -1 \cr } \right ) \]
\( \left (\array{ -2& 2 \cr 6 & -6\cr } \right ) \)
\( \left (\array{ -2& 2 \cr 6 & 6\cr } \right ) \)
\( \left (\array{ -2& 2 \cr 6 & -4\cr } \right ) \)
\( \left (\array{ 2& 2 \cr 6 & 6\cr } \right ) \)