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How do I enter this into Wolfram Alpha?
Solve the equation x^3-5x^2+2x+8=0 given that -1 is a zero of f(x)=x^3-5x^2+2x+8.
Looking for a solution set.
1 Answer
- Julius NLv 77 years agoFavorite Answer
copy/paste: x^3-5x^2+2x+8=0
it will tell you that:
x^3-5x^2+2x+8 = (x+1)(x-2)(x-4)
however, what your teacher wanted you to do was to reduce the polynomial to:
(x^3-5x^2+2x+8) / (x+1) = x^2 - 6x +8
and then use the quadratic formula:
x = (-b ±√(b²-4ac))/(2a) = ( 6±√( 36 -32))/( 2)
positive discriminant = 4; two real roots: x=2 and 4
