a) 6x^2y^5 (-2) x^3y^2z b) (1/5 x^3y^4) (10/9xyz) bài 2 A= -x^2-5yz+z^2 B= 7yz-z^2+5x^2 a) tính A+B b) tính A-B

Question

a) 6x^2y^5 (-2) x^3y^2z
b) (1/5 x^3y^4) (10/9xyz)
bài 2
A= -x^2-5yz+z^2
B= 7yz-z^2+5x^2
a) tính A+B
b) tính A-B

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Thu Thảo 4 years 2021-05-12T12:12:29+00:00 2 Answers 73 views 0

Answers ( )

  1. Verity
    0
    2021-05-12T12:13:44+00:00
    Reply

    *Lời giản

    Bài 1

    `a) 6x^2y^5 (-2) x^3y^2z`

    `= (-2 . 6) (x^2 . x^3) (y^5 . y^2) z`

    `= -12 x^5 y^7 z`

    `b) (1/5 x^3y^4) (10/9 xyz)`

    `= (1/5 . 10/9) (x^3 . x) (y^4 . y) z`

    `= 2/9 x^4 y^5 z`

    Bài 2

    `a) A + B = -x^2 – 5yz + z^2 + 7yz – z^2 + 5x^2`

    `-> A + B = (-x^2 + 5x^2) + (-5yz + 7yz) + (z^2 – z^2)`

    `-> A + B = 4x^2 + 2yz`

    `b) A – B = -x^2 – 5yz + z^2 – 7yz + z^2 – 5x^2`

    `-> A – B = (-x^2 – 5x^2) + (-5yz – 7yz) + (z^2 + z^2)`

    `-> A – B = -6x^2 – 12yz + 2z^2`

  2. Doris
    0
    2021-05-12T12:14:23+00:00
    Reply

    Giải thích các bước giải:

    Bài 1:

    a.Ta có:

    $6x^2y^5(-2)x^3y^2z$ 

    $=-6x^2y^5\cdot \:2x^3y^2z$

    $=-6\cdot -2\cdot x^2\cdot x^3\cdot y^5\cdot y^2\cdot z$

    $=-12x^5y^7z$

    b.Ta có:

    $(\dfrac15x^3y^4)(\dfrac{10}{9}xyz)$

    $=\dfrac15x^3y^4\cdot \dfrac{10}{9}xyz$

    $=\dfrac15\cdot \dfrac{10}9\cdot x^3\cdot x\cdot y^4\cdot y\cdot z$

    $=\dfrac29x^4y^5z$

    Bài 2:

    a.Ta có:

    $A+B=(-x^2-5yz+z^2)+(7yz-z^2+5x^2)$

    $\to A+B=-x^2-5yz+z^2+7yz-z^2+5x^2$

    $\to A+B=z^2-z^2-5yz+7yz+4x^2$

    $\to A+B=2yz+4x^2$

    Ta có:

    $A-B=(-x^2-5yz+z^2)-(7yz-z^2+5x^2)$

    $\to  A-B=-x^2-5yz+z^2-7yz+z^2-5x^2$

    $\to A-B=z^2+z^2-5yz-7yz-x^2-5x^2$

    $\to A-B=2z^2-12yz-6x^2$

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )