Bài 6:A=4x²-3x+x³ B=-2x³-4+2x²-10x³ Tính A+B,A-B

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Bài 6:A=4x²-3x+x³ B=-2x³-4+2x²-10x³
Tính A+B,A-B

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Jade 4 tuần 2021-08-15T22:44:18+00:00 2 Answers 1 views 0

Answers ( )

    0
    2021-08-15T22:45:43+00:00

    Ta có: `A=4x²-3x+x³`

               `B=-2x³-4+2x²-10x³=-12x³+2x²-4`

    Vậy `A+B= 4x²-3x+x³-12x³+2x²-4`

    `⇔A+B=-11x³+6x²-3x-4`

           `A-B=4x²-3x+x³-(-12x³+2x²-4)`

    `⇔A-B=4x²-3x+x³+12x³-2x²+4`

    `⇔A-B=13x³+2x²-3x+4`

     

    0
    2021-08-15T22:45:56+00:00

    Đáp án + Giải thích các bước giải:

    `A+B=4x^{2}-3x+x^{3}-2x^{3}-4+2x^{2}-10x^{3}`

    `=>A+B=(x^{3}-2x^{2}-10x^{2})+(4x^{2}+2x^{2})-3x-4`

    `=>A+B=-11x^{3}+6x^{2}-3x-4`

    `———–`

    `A-B=4x^{2}-3x+x^{3}-(-2x^{3}-4+2x^{2}-10x^{3})`

    `=>A-B=4x^{2}-3x+x^{3}+2x^{3}+4-2x^{2}+10x^{3}`

    `=>A-B=(x^{3}+2x^{3}+10x^{3})+(4x^{2}-2x^{2})-3x+4`

    `=>A-B=13x^{3}+2x^{2}-3x+4`

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