Question 448579
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Hi,
Find all rational roots of the equation 
 x^3-5x^2-4x+20=0   |If x = 2  then 8-20-8-20= 0
 x^3-5x^2-4x+20)/(x-2) = x^2-3x-10
 (x-2)(x^2-3x-10) = 0
           {{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
           {{{x = (3 +- sqrt( 49 ))/(2) }}} 
              x = (3 ± 7)/2   x = 5 and x = -2
 Rational roots are: -2,2,5