首页 > 留学知识库

问题: (X²-5X+1)(X²-5X+9)+15=0

解答:

(X²-5X+1)(X²-5X+9)+15=0
X²-5X=t
(t+1)(t+9)+15=0
t^2+10t+24=0
(t+4)(t+6)=0
t=-4或-6
当t=-4时
x^2-5x=-4
x^2-5x+4=0
(x-1)(x-4)=0
x=1或4
当x=-6时
x^2-5x=-6
x^2-5x+6=0
(x-2)(x-3)=0
x=2或3