What are the solutions to X2 + 8X + 7 = 0?

Question

What are the solutions to X2 + 8X + 7 = 0?

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Thu Cúc 4 years 2021-07-30T09:43:40+00:00 2 Answers 7 views 0

Answers ( )

  1. Vodka
    0
    2021-07-30T09:45:03+00:00
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    Answer:

    x=-1,-7

    Step-by-step explanation:

    x^2+8x+7=0 where a \neq 0 so a = 1 b = 8 c = 7

    Quadratic Formula: x=-b\frac{\sqrt{b^2-4ac} }{2a}

    x=-8\frac{\sqrt{8^2-4(1)(7)} }{2(1)}

    x=-8\frac{\sqrt{64-28} }{2}     Evaluate the exponent and multiply 4ac

    x=-8\frac{\sqrt{36} }{2}          Subtract b^2 – 4ac and multiply 2a

    x=-8\frac{\sqrt{6} }{2}           Solve for the sqrt root of 35

    x = – 8 ± 6/2 =

    x = – 8 + 6/2 = -1

    x = – 8 – 6/2 = -7

  2. kimcuc
    0
    2021-07-30T09:45:13+00:00
    Reply

    Answer:

    x = – 7, x = – 1

    Step-by-step explanation:

    Given

    x² + 8x + 7 = 0

    Consider the factors of the constant term (+ 7) which sum to give the coefficient of the x- term (+ 8)

    The factors are + 7 and + 1 , since

    7 × 1 = 7 and 7 + 1 = 8 , then

    (x + 7)(x + 1) = 0 ← in factored form

    Equate each factor to zero and solve for x

    x + 7 = 0 ⇒ x = – 7

    x + 1 = 0 ⇒ x = – 1

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )