JAMB and WAEC Mathematics questions: Matrices and determinants

25 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Matrices and determinants· JAMB

   If the determinant of [[x, 2], [3, 4]] is 10, find x.

   • A−4
   • B4
   • C1
   • D6

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   Explanation and discussion

2. Question 2· Matrices and determinants· JAMB

   The determinant of the matrix with rows (a, b) and (c, d) is

   • Aac − bd
   • Bab − cd
   • Cad − bc
   • Dad + bc

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   Explanation and discussion

3. Question 3· Matrices and determinants· JAMB

   Find the inverse of the matrix [[2, 1], [1, 1]].

   • A[[−1, 1], [1, −2]]
   • B[[1, 1], [1, 2]]
   • C[[1, −1], [−1, 2]]
   • D[[2, −1], [−1, 1]]

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4. Question 4· Matrices and determinants· JAMB

   Solve [[1, 1], [1, −1]] × [[x], [y]] = [[5], [1]].

   • Ax = 2, y = 3
   • Bx = 3, y = 2
   • Cx = 5, y = 1
   • Dx = 4, y = 1

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5. Question 5· Matrices and determinants· JAMB

   Evaluate the determinant of [[4, −2], [3, 1]].

   • A−2
   • B10
   • C−10
   • D2

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6. Question 6· Matrices and determinants· JAMB

   Find k if the matrix [[1, 2], [3, k]] has no inverse.

   • A6
   • B−6
   • C3/2
   • D2/3

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7. Question 7· Matrices and determinants· JAMB

   If A = [[2, 0], [0, 3]], find A².

   • A[[4, 0], [0, 9]]
   • B[[4, 0], [0, 6]]
   • C[[2, 0], [0, 3]]
   • D[[4, 6], [6, 9]]

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8. Question 8· Matrices and determinants· JAMB

   If [[2, 0], [0, 2]] × [[x], [y]] = [[4], [6]], find x and y.

   • Ax = 2, y = 3
   • Bx = 4, y = 6
   • Cx = 8, y = 12
   • Dx = 1, y = 1.5

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9. Question 9· Matrices and determinants· JAMB

   A 2 × 3 matrix is multiplied by a 3 × 2 matrix. The order of the product is

   • A3 × 3
   • B2 × 2
   • C2 × 3
   • D3 × 2

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10. Question 10· Matrices and determinants· JAMB

    If A = [[1, −1], [2, 0]], find 3A.

    • A[[4, 2], [5, 3]]
    • B[[3, −1], [2, 0]]
    • C[[3, −3], [6, 0]]
    • D[[1, −3], [6, 0]]

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11. Question 11· Matrices and determinants· JAMB

    Evaluate the determinant of [[5, 2], [3, 4]].

    • A20
    • B26
    • C14
    • D6

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    Explanation and discussion

12. Question 12· Matrices and determinants· JAMB

    Find the transpose of [[1, 2], [3, 4]].

    • A[[1, 2], [3, 4]]
    • B[[4, 3], [2, 1]]
    • C[[1, 3], [2, 4]]
    • D[[−1, −2], [−3, −4]]

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13. Question 13· Matrices and determinants· JAMB

    Find the product [[1, 2], [0, 1]] × [[3], [4]].

    • A[[11], [7]]
    • B[[3], [8]]
    • C[[7], [4]]
    • D[[11], [4]]

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14. Question 14· Matrices and determinants· JAMB

    The matrix with rows (x, 4) and (3, x) is singular. Find x.

    • A±2√3
    • B±12
    • C±4
    • D±3

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15. Question 15· Matrices and determinants· JAMB

    If A = [[2, 1], [3, 4]], find A².

    • A[[4, 2], [6, 8]]
    • B[[4, 1], [9, 16]]
    • C[[7, 5], [18, 16]]
    • D[[7, 6], [18, 19]]

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16. Question 16· Matrices and determinants· JAMB

    Find the inverse of the matrix with rows (3, 1) and (5, 2).

    • Arows (−2, 1) and (5, −3)
    • Brows (2, 1) and (5, 3)
    • Crows (2, −1) and (−5, 3)
    • Drows (3, −1) and (−5, 2)

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17. Question 17· Matrices and determinants· JAMB

    Find the inverse of [[3, 1], [5, 2]].

    • A[[−2, 1], [5, −3]]
    • B[[2, 1], [5, 3]]
    • C[[3, −1], [−5, 2]]
    • D[[2, −1], [−5, 3]]

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18. Question 18· Matrices and determinants· JAMB

    The matrix [[2, x], [x, 8]] is singular. Find x.

    • A±2
    • B4 only
    • C±4
    • D16

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19. Question 19· Matrices and determinants· JAMB

    Solve 2x + 3y = 13 and x − y = −1.

    • Ax = 4, y = 5
    • Bx = 3, y = 2
    • Cx = 1, y = 2
    • Dx = 2, y = 3

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20. Question 20· Matrices and determinants· JAMB

    Evaluate the determinant of [[1, 0, 0], [0, 2, 0], [0, 0, 3]].

    • A1
    • B0
    • C5
    • D6

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    Explanation and discussion