# Worksheet: Solution Cases of System of Linear Equations

In this worksheet, we will practice determining whether a linear system of equations has a unique solution, no solution, or an infinite number of solutions.

**Q2: **

Determine the number of solutions to the following system:

- AThere are infinitely many solutions.
- BThere are finitely many solutions, not including .
- CThe only solution is .
- DThere are no solutions.

**Q6: **

Determine the number of solutions to the following system:

- AThere are infinitely many solutions.
- BThere are finitely many solutions, not including .
- CThe only solution is .
- DThere are no solutions.

**Q7: **

Determine the number of solutions to the following system:

- AThe only solution is .
- BThere are finitely many solutions, not including .
- CThere are no solutions.
- DThere are infinitely many solutions.

**Q9: **

If there is a unique solution to a system of linear equations, which of the following must be true of the columns in the augmented matrix?

- AThe last one must not be a pivot, and the ones to the left must each be pivot columns.
- BThe last one must be a pivot, and the ones to the left must each be pivot columns.
- CThe last one must not be a pivot, and the ones to the left must not each be pivot columns.
- DThe last one must be a pivot, and the ones to the left must not each be pivot columns.

**Q10: **

In the given augmented matrix, * denotes an arbitrary number and ■ denotes an arbitrary nonzero number. Determine whether the given augmented matrix is consistent and, if it is consistent, whether its solution is unique:

- AThe matrix is consistent and its solution is unique.
- BThe matrix is inconsistent.
- CThe matrix is consistent and its solution is not unique.

**Q11: **

In the augmented matrix denotes an arbitrary number and denotes a nonzero number. Determine whether the given augmented matrix is consistent. If it is consistent, is the solution unique?

- AThe matrix is consistent and there is a unique solution.
- BThe matrix is inconsistent.
- CThe matrix is consistent and there is no unique solution.

**Q12: **

In the augmented matrix denotes an arbitrary number and denotes an arbitrary nonzero number. Determine whether the given augmented matrix is consistent and, if it is consistent, whether its solution is unique.

- AThe matrix is consistent and its solution is not unique.
- BThe matrix is consistent and its solution is unique.
- CThe matrix is inconsistent.

**Q15: **

Find conditions on and for the following augmented matrix to have no solution, a unique solution, and infinitely many solutions:

- AIf , then there is exactly one solution. If and , then there are no solutions. If and , then there are infinitely many solutions.
- BIf , then there is exactly one solution. If and , then there are no solutions. If and , then there are infinitely many solutions.
- CIf , then there is exactly one solution. If and , then there are no solutions. If and , then there are infinitely many solutions.
- DIf , then there is exactly one solution. If and , then there are no solutions. If and , then there are infinitely many solutions.
- EIf , there are infinitely many solutions. If and , there are no solutions. If and , there will be a unique solution.

**Q18: **

Find conditions on and for the augmented matrix to have no solution, a unique solution, and infinitely many solutions.

- AIf , there will be a unique solution for any . If and , there are no solutions. If and , then there are infinitely many solutions.
- BIf , there will be a unique solution. If and , there are no solutions. If and , then there are infinitely many solutions.
- CIf , there are infinitely many solutions. If and , there are no solutions. If and , there will be a unique solution.
- DIf , there are infinitely many solutions. If and , there are no solutions. If and , there will be a unique solution.
- EIf , there are infinitely many solutions. If and , there are no solutions. If and , there will be a unique solution.

**Q22: **

Suppose is matrix in and is a vector in and consider this statement: there exists a solution to the equation . Which of the following is true?

- AThe statement is always true.
- BIf is nonsingular, then the statement is true.
- CIf the statement is true, then is nonsingular.
- DIf is nonsingular, then the statement is false.
- EThe statement is true if and only if is nonsingular.