解二元一次方程2x^2-8x+4=0

问题描述:

解二元一次方程2x^2-8x+4=0

=x^2-4x+2=x^2-4x+4-2=====>(x-2)^2=2 x=2+正负根2

x=正根号2或负根号2

2x^2-8x+4=0
x^2-4x+2=0
x^2-4x+4-2=0
x^2-4x+4=2
(x-2)²=2
x-2=±√2
x=2±√2