去括号(4x-3y)-[-(3-x)+(x-y)]-5x 还是去括号4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}

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去括号(4x-3y)-[-(3-x)+(x-y)]-5x还是去括号4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²

去括号(4x-3y)-[-(3-x)+(x-y)]-5x 还是去括号4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}
去括号(4x-3y)-[-(3-x)+(x-y)]-5x 还是去括号4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}

去括号(4x-3y)-[-(3-x)+(x-y)]-5x 还是去括号4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}
4x-3y-[-3+x+x-y]-5x
=4x-3y+3-2x+y-5x
=-3x-2y+3
去括号先从里面去 后依次向外 一样的要合并
4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}
=4xy²-3x²y-3x²-xy²+[2xy²-4x²y+(x²y-2xy²)]}
=4xy²-3x²y-3x²-xy²+2xy²-4x²y+x²y-2xy²
=3xy²-6x²y-3x²

(4x-3y)-[-(3-x)+(x-y)]-5x=(4x-3y)+(3-x)-(x-y)-5x=4x-3y+3-x-x+y-5x=3-2y-3x
4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}=4xy²-3x²y-3x²-xy²+[...

全部展开

(4x-3y)-[-(3-x)+(x-y)]-5x=(4x-3y)+(3-x)-(x-y)-5x=4x-3y+3-x-x+y-5x=3-2y-3x
4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}=4xy²-3x²y-3x²-xy²+[2xy²-4x²y+(x²y-2xy²)]}=4xy²-3x²y-3x²-xy²+2xy²-4x²y+x²y-2xy²=3xy²-6x²y-3x²

收起

小兄弟, 这种题考得 是负负得正的问题, 这个问题记住了, 就会解了.

(4x-3y)-[-(3-x)+(x-y)]-5x
=4x-3y+(3-x)-(x-y)-5x
=4x-3y+3-x-x+y-5x
=-3x-2y+3
4xy²-3x²y-{3x²+xy²-[2xy²-4x²y+(x²y-2xy²)]}
=4xy^2-3x^2y-[3x^2+xy^2-(2xy^2-4x^2y+x^2y-2xy^2)]
=4xy^2-3x^2y-(3x^2+xy^2+3x^2y)
=4xy^2-3x^2y-3x^2-xy^2-3x^2y
=3xy^2-6x^2y-3x^2