kennadir
Answered

  1. Complete the square to form a perfect square trinomial. 8x + x² + __
A16
B4
C8
D2

  1. Solve the equation by completing the square. x² + 4x = 12
A3, -4
B-6, 2
C4, -4
D-4, 3

  1. Find the number of real solutions using the discriminant. x² + 9x + 4 = 0
A0
B1
C2

  1. Find the number of real solutions using the discriminant. x² - 6x - 7 = 0
A2
B1
C0

Verified Answer :

Panoyin
  1. x² + 8x + 16
        x² + 4x + 4x + 16
        x(x) + x(4) + 4(x) + 4(4)
        x(x + 4) + 4(x + 4)
        (x + 4)(x + 4)
        (x + 4)²
    The answer is A.

    2.                           x² + 4x = 12
                            x² + 4x + 4 = 12 + 4
                            x² + 4x + 4 = 16
                    x² + 2x + 2x + 4 = 16
        x(x) + x(2) + 2(x) + 2(2) = 16
                 x(x + 2) + 2(x + 2) = 16
                         (x + 2)(x + 2) = 16
                                  (x + 2)² = 16
                                √(x + 2)² = √16
                                     x + 2 = ±4
                                        - 2    - 2
                                          x = -2 ± 4
                                          x = -2 + 4    or    x = -2 - 4
                                          x = 2       or        x = -6
    The answer is B.

    3. x² + 9x + 4 = 0
        Δ = b² - 4ac
        Δ = (9)² - 4(1)(4)
        Δ = 81 - 4(4)
        Δ = 81 - 16
        Δ = 65
    THe answer is C.

    4. x² - 6x - 7 = 0
        Δ = b² - 4ac
        Δ = (-6)² - 4(1)(-7)
        Δ = 36 - 4(-7)
        Δ = 36 + 28
        Δ = 64
    The answer is A.

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