此题只能用“公式法”
把字母m看作未知数,解一元二次方程5m^2-2mn-2n^2=0
Δ=4n^2+40n^2=44n^2
m1=(1+√11)n/5,m2=(1-√11)n/5
所以5m^2-2mn-2n^2＝5(m-(1+√11)n/5)(m-(1-√11)n/5)=(5m-(1+√11)n)(m-(1-√11)n/5)
此题只能用“公式法”
把字母m看作未知数,解一元二次方程5m^2-2mn-2n^2=0
Δ=4n^2+40n^2=44n^2
m1=(1+√11)n/5,m2=(1-√11)n/5
所以5m^2-2mn-2n^2＝5(m-(1+√11)n/5)(m-(1-√11)n/5)=(5m-(1+√11)n)(m-(1-√11)n/5)