###### Exercise 3

Give an example of a reduced row echelon matrix that describes a linear system having the stated properties. If it is not possible to find such an example, explain why not.

Write a reduced row echelon matrix for a linear system having five equations and three unknowns and having exactly one solution.

Write a reduced row echelon matrix for a linear system having three equations and three unknowns and having no solution.

Write a reduced row echelon matrix for a linear system having three equations and five unknowns and having infinitely many solutions.

Write a reduced row echelon matrix for a linear system having three equations and four unknowns and having exactly one solution.

Write a reduced row echelon matrix for a linear system having four equations and four unknowns and having exactly one solution.