题目

(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

提问时间：2020-10-17

答案

(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...