解方程:(x-4)[50-10x+50]=50
问题描述：
解方程:(x-4)[50-10x+50]=50
答
5,9
答
(x-4)[10-x]=5
10x-x^2-40+4x=5
14x-x^2-40=5
x^2-14x+45=0
(x-5)(x-9)=0
x=5或x=9
答
(x-4)[50-10x+50]=50
(x-4)[100-10x]=50
(x-4)[10-x]=5
10x-x^2-40+4x=5
14x-x^2-40=5
x^2-14x+45=0
(x-5)(x-9)=0
x=5或x=9
答
两边除以-10
(x-4)(x-10)=-5
x²-14x+40=-5
x²-14x+45=0
(x-5)(x-9)=0
x=5,x=9