1 x^2n-1+5x^2n+2-7x^2n=-x^2n+1=-1+1=0
2 3c^2-8c-13c^2+2c+3=-10c^2-6c+3=-160+24+3=-133
3 -3x^m-1y^4与1/3x^2yn+2是同类项 m-1=2 4=n+2 m=3 n=2
4 代数式2x^3-3x^2y+mx^2y-3x^2怎么
1 x^2n-1+5x^2n+2-7x^2n=-x^2n+1=-1+1=0
2 3c^2-8c-13c^2+2c+3=-10c^2-6c+3=-160+24+3=-133
3 -3x^m-1y^4与1/3x^2yn+2是同类项 m-1=2 4=n+2 m=3 n=2
4 代数式2x^3-3x^2y+mx^2y-3x^2怎么