SOLUTION: Find the domain of (f/g)(x) when f(x)=2x^2-5x and g(x)=x^2-2x-7

Question 510925: Find the domain of (f/g)(x) when f(x)=2x^2-5x and g(x)=x^2-2x-7
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Find the domain of (f/g)(x) when f(x)=2x^2-5x and g(x)=x^2-2x-7
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(f/g)(x) = (2x^2-5x)/(x^2-2x-7)
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Factor:
= (x(2x-5))/(x^2-2x-7)
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Since b^2 - 4ac = 2^2-4*1*-7 = 4+28 >0
x = [2 +- sqrt(4+28)]/2
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x = [2 +- sqrt(32)]/2
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x = [2 +- 4sqrt(2)]/2
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x = 1 + 2sqrt(2) or x = 1-2sqrt(2)
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These Real numbers are missing from the domain which is otherwise
All Real Numbers.
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Cheers,
Stan H.
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