PLEASE solve the quadratic equation by factoring. (x + 1)(x − 3) = 5?

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  • MyRank
    Lv 6
    4 years ago

    (x+1) (x-3) = 5

    Multiplied by (x+1) × (x-3)

    (x² – 3x + x – 3)

    (x² – 2x – 3) = 5

    x² – 2x – 3 – 5 = 0

    x² – 2x – 8 = 0

    compare the quadratic

    ax² + bx + c = 0

    x² – 2x – 8 =0

    x² – 4x + 2x – 8 = 0

    x(x – 4) + 2(x – 4) = 0

    (x – 4) (x + 2) = 0

    (x – 4) = 0

    x = 4

    x + 2 = 0

    x = - 2

    Verified :

    x² – 2x – 8 = 0

    put x = 4

    (4)² – 2(4) – 8 = 0

    16 – 16 = 0

    0 = 0

    x² – 2x – 8 = 0

    put x = -2

    (-2)² – 2(-2) – 8 = 0

    4 + 4 – 8 = 0

    0 = 0.

  • 4 years ago

    x=4 x=-2

  • 4 years ago

    Apply FOIL

    x^2 - 3x + x - 3 = 5

    x^2 - 2x - 8 = 0

    (x - 4)(x + 2) = 0

    x -4 = 0

    x = 4

    &

    x + 2 = 0

    x = -2

  • Anonymous
    4 years ago

    expand as x² - 2x - 3 = 5

    put into standard equation form: x² - 2x - 8 = 0

    factor: (x - 4)(x + 2) = 0

    can you take it from here so you can tell your instructor that you “completed” the exercise? if not, gl!

    i would give you the final answer to your question, but then you would have to split the credit with me...

    i am sure one of my y!a colleagues shall supply you with the specific answer to this exercise... but that shall not help you next time, and there shall be a next time!

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  • Colin
    Lv 7
    4 years ago

    (x + 1)(x − 3) = 5

    Multiply out...

    x^2 - 3 - 2*x = 5

    Collect like terms...

    x^2 - 2*x - 8 = 0

    Factorise...

    (x - 4)*(x + 2) = 0

    Solve...

    x = 4 or x = -2

  • DWRead
    Lv 7
    4 years ago

    (x+1)(x-3) = 5

    x²-2x-3 = 5

    x²-2x-8 = 0

    (x-4)(x+2) = 0

    x = 4,-2

  • Anonymous
    4 years ago

    (x+1)(x-3) = 5

    x^2-2x-3=5

    x^2-2x-8=0

    (x-4)(x+2) = 0

    x=4 or x=-2

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