We have to find the roots of : x^3 – 2x^2 – 23x +
60
x^3 – 2x^2 – 23x + 60 =
0
As the equation has a highest power of x, we will have 3
roots.
From the numeric term equal to 60 we know that the
product of the roots is 60, substituting values 1,-1, 2, -2 and 3, we get that 3 is a
root. So now we have to factor out x – 3, the other roots have a product of
20.
x^3 – 2x^2 – 23x + 60 =
0
(x^3 + x^2 – 20x – 3x^2 – 3x + 60) =
0
(x – 3)(x^2 + x – 20) =0
(x
– 3)( x^2 + 5x – 4x – 20) = 0
We can factorize the
quadratic term as 5* -4 = -20 and 5 - 4 = 1
(x – 3)( x(x +
5) – 4(x + 5)) = 0
(x – 3)(x – 4)(x + 5) =
0
This gives the roots of x^3 – 2x^2 – 23x + 60 as x = 3 ,
x = 4 and x = -5.
The required roots are
x = 3 , x = 4 and x =
-5.
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