單項(xiàng)式2/3x^m y^2與-2x^4 y的次數(shù)相同
2/3x^m y^2的次數(shù)為m+2
-2x^4y的次數(shù)為4+1=5
∴m+2=5
∴m=3
∵x=-1,y=-3,
∴2/3x^my^2-2x^4y
=2/3x^3y^2-2x^4y
=-2/3*(-3)²-2*(-3)
=-6+6
=0