Question

关于x,y得多项式（5m+1)x^2y+(4n-2)xy^2-3x+y-(-2m-6)x^2y+(3-3n)xy^2 不

Answer 1

（5m+1)x^2y+(4n-2)xy^2-3x+y-(-2m-6)x^2y+(3-3n)xy^2

=(7m+7)x^2y+(n+1)xy^2-3x+y

不含三次项

7m+7=0,n+1=0

m=-1,n=-1

5m+2n=-5-2=-7