Saturday, December 27, 2014

Solve the equation x^3 - 2x^2 - x + 2 = 0

To solve the equation, we'll group the first 2 terms together and the next 2 terms together, so that we can factorize:


(x^3 - 2x^2) - (x - 2) = 0


x^2(x - 2) - (x - 2) = 0


We'll factorize again:


(x - 2)(x^2 - 1) = 0


We'll put each factor as being 0.


x-2 = 0


x = 2


x^2 - 1 = 0


The expression is a difference of squares:


x^2 - 1 = (x - 1)(x + 1) = 0


x-1 = 0


x = 1


x + 1 = 0


x = -1


The solutions of the equation are: {-1,1,2}.

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