CleverSphere

Linear algebra practice exam with answers

4 questions · 28 points · about 45 minutes

  1. Question 1

    8 points

    How many solutions does the system have?

    Bring the augmented matrix to row echelon form and compare rank(A) with rank(A|b).

    2−11−4
    0231
    −2−1−43

    Your answer

  2. Question 2

    8 points

    Find the rank of the matrix.

    Bring the matrix to row echelon form and count the rows that are not all zeros.

    1−231
    1−235
    −24−6−4
    1−233

    Your answer

  3. Question 3

    8 points

    Solve the system of linear equations.

    Use row operations until you can read off the solution, then enter it below.

    −4−8122−18
    −4−76−4−1
    −2−54−41
    −2−32−21

    x₁, x₂, x₃, x₄ | b

    Your answer

  4. Question 4

    4 points

    Calculate the determinant.

    Swapping rows flips the sign; multiplying a row by k multiplies the determinant by k. Adding a multiple of another row changes nothing.

    −212
    212
    402

    Your answer