Question 200569: Without solving the equation,or factoring, determine the solution(s) to the equation, -x^2+4x+5=0
Found 2 solutions by Alan3354, RAY100:
Answer by Alan3354(69443)   (Show Source):
Answer by RAY100(1637)  (Show Source):
You can put this solution on YOUR website! One way to solve eqn without formal techniques is a modified graphing technigue
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-x^2 +4x +5 =0
mult thru by -1
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x^2 -4x -5 =0,,,,(could have left it alone but personal preference is to have x^2 a positive )
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We are looking for which x"s make this expression = 0
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Let D = x^2 -4x -5,,,make a T BOx
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X,,,,,,,,,,,,,,D
0.............-5
1,,,,,,,,,,,,,-8
2,,,,,,,,,,,,,-5
3,,,,,,,,,,,,,-8
4,,,,,,,,,,,,,-4
5,,,,,,,,,,,,,0,,,,,,,,,one answer
6,,,,,,,,,,,,,,7
-1,,,,,,,,,,,,,0,,,,,,,,another answer
-2,,,,,,,,,,,,7
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If a rough plot is made, we see a y parabola , pointed up, with vertex at (2,-9)
x intercepts at x=-1, x=+5
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Have a nice day
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