SOLUTION: Find the distance between the points of intersection of the graphs of y = 2x^2 – 4x+ 1 and 2x - y = - 21.

Algebra ->  Coordinate-system -> SOLUTION: Find the distance between the points of intersection of the graphs of y = 2x^2 – 4x+ 1 and 2x - y = - 21.      Log On


   

Question 1073212: Find the distance between the points of intersection of the graphs of y = 2x^2 – 4x+ 1 and 2x - y = - 21.
Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
2x-%282x%5E2-4x%2B1%29=-21
2x-2x%5E2%2B4x-1%2B21=0
-2x%5E2%2B6x%2B20=0
2x%5E2-6x-20=0
* highlight_green%28x%5E2-3x-10=0%29
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discrim, 9%2B4%2A10=49=7%5E2
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x=%283%2B-+7%29%2F2
system%28x=-2%2Cor%2Cx=5%29
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Corresponding y values:
y=2x%2B21
If x=-2, then y=17.
Point (-2,17).
If x=5, then y=31.
Point (5,31).


Distance between the intersection points:
sqrt%28%285-2%29%5E2%2B%2831-17%29%5E2%29
sqrt%289%2B48%29
highlight%28sqrt%2857%29%29


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Better if you recognized the * quadratic equation is factorable.