SOLUTION: How do I solve the polynomial equation: (x+2)(x-7)=-18

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Question 409458: How do I solve the polynomial equation:
(x+2)(x-7)=-18
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

solving

(x+2)(x-7)= -18      |(x+2)(x-7) =  x(x-7)+2(x-7) = x^2 -7x +2x -14

 x^2 -5x - 14 = -18

(x -5/2)^2 - 25/4  -14 = -18  |completing the square

   (x -5/2)^2 = -4 + 25/4

   (x-5/2)^2 = 2.25            |taking square root of both sides of eequation

    x - 5/2 = ± 1.5

      x = 5/2 ± 3/2

      x = 4

      x = 1

CHECKING our Answer(s)***

  (x+2)(x-7)= -18

     6*-3 = -18

     3*-6 = -18