1.如果2x-y=5,那么3-4x+2y=（）2.x^2m-1*y^2与-2/5x^5*y^n+1合并后为单项式,则m^2-n^2=()3.(）＋3x^3-2x^2*y-3xy^2+4y^3=-x^3+4xy^2-7y^34.若A=5x^3+6y^3-3/2xy^2,B=-1/3y^2+3/4xy^2+3x^3,则2A-3B=()

Question

1.如果2x-y=5,那么3-4x+2y=（ ）
2.x^2m-1*y^2与-2/5x^5*y^n+1合并后为单项式,则m^2-n^2=( )
3.( ）＋3x^3-2x^2*y-3xy^2+4y^3=-x^3+4xy^2-7y^3
4.若A=5x^3+6y^3-3/2xy^2,B=-1/3y^2+3/4xy^2+3x^3,则2A-3B=( )

Answer 1

1. -7
2. 8
3. -2x^2+7xy^2-11y^3+2x^2y
4. x^3+12y^3-21/4xy^2+y^2