Question

x3-4x+3=0求根

x3-4x+3=0求根

Answer 1

x³-x-3x+3=0
x(x²-1)-3(x-1)=0
(x-1)(x²+x-3)=0
x-1=0，那么x=1
x²+x-3=0
那么x=(-1±√13)/2

Answer 2

f(x) =x^3-4x+3
f(1)=0
x^3-4x+3 =(x-1)(x^2+ax-3)
coef. of x
-3-a=-4
a=1

x^3-4x+3=0
(x-1)(x^2+x-3)=0
x=1 or (-1+√13)/2 or (-1-√13)/2