几道因式分解的题目、、

来源：百度知道 编辑：UC知道 时间：2024/05/14 07:22:38
若m-n=-2，m²+n²/2-mn

若x=156,y=144,则1/2x²+xy+1/2y²=

2道题目、、过程、

若m-n=-2，m²+n²/2-mn
（m^2+n^2）/2 -mn
=(m^2+n^2-2mn)/2
=(m-n)^2/2
=(-2)^2/2
=4/2
=2

若x=156,y=144,则1/2x²+xy+1/2y²=
1/2x^2+xy+1/2y^2
=1/2*(x^2+2xy+y^2)
=1/2*(x+y)^2
=1/2*(156+144)^2
=1/2*300^2
=1/2*90000
=45000

m-n=-2，m²+n²/2-mn
（m^2+n^2）/2 -mn
=(m^2+n^2-2mn)/2
=(m-n)^2/2
=(-2)^2/2
=4/2
=2

x=156,y=144,则1/2x²+xy+1/2y²=
1/2x^2+xy+1/2y^2
=1/2*(x^2+2xy+y^2)
=1/2*(x+y)^2
=1/2*(156+144)^2
=1/2*300^2
=1/2*90000
=45000

(m^2+n^2)/2-mn=(m^2-2mn+n^2)/2=(m-n)^2/2=(-2)^2/2=2;x^2/2+xy+y^2/2=(x^2+2xy+y^2)/2=(x+y)^2/2=(156+144)^2/2=300^2/2=45000