2x²-8xy+5y²因式分解怎么做

2x^2-8xy+5y^2
=(2x^2-8xy+8y^2)-3y^2
=(√2x-2√2y)^2-(√3y)^2
=(√2x-2√2y+√3y)(√2x-2√2y-√3y)
=[√2x-(2√2-√3)y][√2x-(2√2+√3)y]

先解出方程的2个根
x=2+[6^(1/2)]/2 or 2-[6^(1/2)]/2
然后可以把式子写成
{x - 2+[6^(1/2)]/2}*{x-{2-[6^(1/2)]/2}}