document.write( "Question 106110: The sign of the discriminant D is positive as the parabola opens upward.
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document.write( "We observe the x intercepts to be –1, and 0.67
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document.write( "So the function is written as y = a(x – (-1)) (x – 0.67) where ‘a’ is a constant.
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document.write( "y = a (x + 1) (x – 0.67)
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document.write( "The lowest point of the parabola is the vertex.
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document.write( "Now the parabola passes through (- 0.16, -2)
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document.write( "-2 = a( - 0.16 + 1) ( - 0.16 – 0.67)
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document.write( "-2 = a(0.84) (- 0.83)
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document.write( "a = -2/ (0.84)(- 0.83)
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document.write( "a = 2.87
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document.write( "Thus the quadratic equation is y = 2.87 ( x + 1) (x – 0.67)
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document.write( "Or y = 2.87 (x2 + 0.33x – 0.67)
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document.write( "The quadratic equation is 2.87 ( x2 + 0.33x – 0.67 ) = y
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document.write( "To solve for x, we equate y to 0.
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document.write( "x2 + 0.33x – 0.67 = 0
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document.write( "x2 + 0.33x – 0.67 = 0
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document.write( "x2 + x – 0.67 x – 0.67 = 0
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document.write( "x (x + 1) – 0.67 ( x + 1) = 0
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document.write( "(x + 1) (x – 0.67) = 0
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document.write( "X + 1 = 0 or x – 0.67 = 0
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document.write( "X = -1 or x = 0.67
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document.write( "The solution is x = -1 or x = 0.67\r
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document.write( "This is a discussion group question. One of the girls on my team came up with this but I can't figure out where she got the 0.33x. I thought I was getting it but now I am confused. Can you explain this? Please, Please! \n" );
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Algebra.Com's Answer #77200 by Fombitz(32388)![]() ![]() You can put this solution on YOUR website! Look at this part of the discussion when you multiplied the factors together. \n" ); document.write( " \n" ); document.write( "Use the FOIL method (First Outer Inner Last) \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "I hope this answers your question. \n" ); document.write( " |