b)P=(x/4)^2+(y/2)^2 bt xy=-6; x+2y=0 nếu đề sai thì sửa hộ nha

Question

b)P=(x/4)^2+(y/2)^2 bt xy=-6; x+2y=0 nếu đề sai thì sửa hộ nha

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Bơ 5 years 2020-11-06T09:25:40+00:00 1 Answers 69 views 0

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  1. Philomena
    0
    2020-11-06T09:27:16+00:00
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    Đáp án: $P=\dfrac{3}{2}$

    Giải thích các bước giải:

    Ta có:
    $x+2y=0\to x=-2y$
    Mà $xy=-6\to -2y\cdot y=-6\to y^2=3$
    $\to P=\left(\dfrac{x}{4}\right)^2+\left(\dfrac{y}{2}\right)^2$
    $\to P=\left(\dfrac{-2y}{4}\right)^2+\left(\dfrac{y}{2}\right)^2$

    $\to P=\left(\dfrac{-y}{2}\right)^2+\left(\dfrac{y}{2}\right)^2$

    $\to P=\dfrac{y^2}{4}+\dfrac{y^2}{4}$

    $\to P=\dfrac{y^2}{2}$

    $\to P=\dfrac{3}{2}$

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