问题
选择题
一元二次方程x(x-2)=2-x的根是【 】
A.-1
B.2
C.1和2
D.-1和2
答案
答案:D
解:x(x-2)=2-x,
x2-2x=2-x,
x2-2x+x-2=0,
x2-x-2=0,
(x-2)(x+1)=0,
x-2=0或x+1=0,
解得x1=2,x2=-1;
故答案为x1=-1,x2=2
一元二次方程x(x-2)=2-x的根是【 】
A.-1
B.2
C.1和2
D.-1和2
答案:D
解:x(x-2)=2-x,
x2-2x=2-x,
x2-2x+x-2=0,
x2-x-2=0,
(x-2)(x+1)=0,
x-2=0或x+1=0,
解得x1=2,x2=-1;
故答案为x1=-1,x2=2