求解快10.3x^2y^3,2x^2y,-5x^3y^3z的公因式是____.

3x^2y^3,2x^2y,-5x^3y^3z的公因式是 x^2y
若（a+m)(a-1)=a^2-3a+n,则m+n的值为 0
a^2+(m-1)a-m=a^2-3a+n
得：m-1=-3 即：m=-2
-m=n 得：n=2
已知a^2+b^2=1,x^2+y^2=1,求（ax+by)^2+(bx-ay)^2
（ax+by)^2+(bx-ay)^2
=a^2x^2+2axby+b^2y^2+b^2x^2-2bxay+a^2y^2
=a^2(x^2+y^2)+b^2(x^2+y^2)
=(a^2+b^2)(x^2+y^2)
=1