1.M^2(M-1)-4(1-M)^22.49(2m-2x)^2-9(m+x)^23.(3x+4y)-(4y-3x)^24.(x-2)(x-4)+1最好有一点过程

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1.M^2(M-1)-4(1-M)^22.49(2m-2x)^2-9(m+x)^23.(3x+4y)-(4y-3x)^24.(x-2)(x-4)+1最好有一点过程
1.M^2(M-1)-4(1-M)^2
2.49(2m-2x)^2-9(m+x)^2
3.(3x+4y)-(4y-3x)^2
4.(x-2)(x-4)+1
最好有一点过程

1.M^2(M-1)-4(1-M)^22.49(2m-2x)^2-9(m+x)^23.(3x+4y)-(4y-3x)^24.(x-2)(x-4)+1最好有一点过程
1.M^2(M-1)-4(1-M)^2
=(M-1)[M^2-4(M-1)]
=(M-1)(M^2-4M+4)
=(M-1)(M+2)^2
2.49(2m-2x)^2-9(m+x)^2
=[7(2m-2x)+3(m+x)][7(2m-2x)-3(m+x)]
=(17m-11x)(11m-17x)
3.(3x+4y)^2-(4y-3x)^2
=[(3x+4y)+(4y-3x)][(3x+4y)-(4y-3x)]
=8y*6x
=48xy
4.(x-2)(x-4)+1
=x^2-6x+8+1
=x^2-6x+9
=(x-3)^2