1.(2a+b)(2a-3b)+a(2a+b)2.(x+y)^2-4(x+y-1)3.1/4a^4-1/2a^3+1/4a^2

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1.(2a+b)(2a-3b)+a(2a+b)2.(x+y)^2-4(x+y-1)3.1/4a^4-1/2a^3+1/4a^2

1.(2a+b)(2a-3b)+a(2a+b)2.(x+y)^2-4(x+y-1)3.1/4a^4-1/2a^3+1/4a^2
1.(2a+b)(2a-3b)+a(2a+b)
2.(x+y)^2-4(x+y-1)
3.1/4a^4-1/2a^3+1/4a^2

1.(2a+b)(2a-3b)+a(2a+b)2.(x+y)^2-4(x+y-1)3.1/4a^4-1/2a^3+1/4a^2
1.(2a+b)(2a-3b)+a(2a+b)
=(2a+b)(2a-3b+a)
=(2a+b)(3a-3b)
=3(2a+b)(a-b)
2.(x+y)^2-4(x+y-1)
=(x+y)^2-4(x+y)+4
=[(x+y)-2]^2
=(x+y-2)^2
3.1/4a^4-1/2a^3+1/4a^2
=1/4*a^2(a^2-2a+1)
=1/4*a^2*(a-1)^2

1、原式=(2a+b)(2a-3b+a)=(2a+b)(3a-3b)=3(2a+b)(a-b)
2\原式=(x+y)的平方-4(x+y)+4=(x+y-2)的平方