用因式分解法如何解方程?(x-1)²+3(x-1)+2因式分解法...(m-1)x²-(2m+2)x+m+3+0

问题描述:

用因式分解法如何解方程?
(x-1)²+3(x-1)+2
因式分解法...
(m-1)x²-(2m+2)x+m+3+0

(x-1)^2+3(x-1)+2 =0 设x+1=a
a^2+3a+2=0
(a+2)(a+1)=0
(x+3)(x+2) =0
x1=-3 x2=-2
(m-1)x^-(2m+2)x+m+3=0
(m-1)x^-2(m+1)x+m+3=0 设 m-1=a
ax^2-2(a+2)x+a+4=0
ax^2-2ax+a-4x+4=0
a(x-1)^2-4(x-1)=0
(a-4)(x-1)^2=0
x=1

=((X-1)+2)*((X-1)+1)
=(X+1)*X

原式=x²-2x+1+3x-3+2
=x²+x
=x(x+1)
解补充题:用十字相乘法分解
原式=[(m-1)x-(m+3)](x-1)
=(x-1)[(m-1)x-m-3]