x=y+3,则x-y=3
4分之一（x-y）的平方-0.3（x-y）+0.75（x-y）的平方+10分之3（x-y）-2（x-y）+7
=0.25(x-y)²+0.75(x-y)²-0.3(x-y)+0.3(x-y)-2(x-y)+7
=(x-y)²-2(x-y)+7
=3²-2×3+7
=9-6+7
=10
x=y+3
则x-y=3
4分之一（x-y）的平方-0.3（x-y）+0.75（x-y）的平方+10分之3（x-y）-2（x-y）+7
=1/4*(x-y)^2-0.3(x-y)+0.75(x-y)^2+3/10*(x-y)-2(x-y)+7
=1/4*(x-y)^2-3/10*(x-y)+3/4*(x-y)^2+3/10*(x-y)-2(x-y)+7
=(1/4+3/4)*(x-y)^2-2(x-y)+7
=(x-y)^2-2(x-y)+7
=(x-y)(x-y-2)+7
=3*(3-2)+7
=3+7
=10
h
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024