Question

初一数学的同类项化简，很简单哦！

(1)M^2+M-3M^2-5M+2M^2+4=? (M=-3/4) (2)(A+B)^2-2(A+B)^2+3(A+B)^2=? (A=-2 B=1/3) (3)2/3A^2-6A^3+5A-1/4+5A^3-1/2-4/3A^2=? (A=-3) (4)5XY-3/2X^3Y^2-4XY+1/2X^3Y^2-1/2XY-3X^3Y^2-5=? (X=-1 Y=-2) (5)已知：2M^2N+2MN-3NM^2-3NM+43^2N 其中M是最小正整数，N是绝对值等于1的数

Answer 1

(1)M^2+M-3M^2-5M+2M^2+4
=4-4M=7
(2)(A+B)^2-2(A+B)^2+3(A+B)^2
=2(A+B)^2=50/9
(3)2/3A^2-6A^3+5A-1/4+5A^3-1/2-4/3A^2
=-1/2+5A-2/3A^2-A^3=-105,1/2=-211/2
(4)5XY-3/2X^3Y^2-4XY+1/2X^3Y^2-1/2XY-3X^3Y^2-5
=-4X^3Y^2+1/2XY-5=12
(5)最后一项(43^2N
)是不是4M^2N?
其中M是最小正整数，M=1;N是绝对值等于1的数N=+/-1
2M^2N+2MN-3NM^2-3NM+4M^2N
=3M^2N-NM
=5N=+/-5