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a: \(\left(2x-y+7\right)^{2022}>=0\forall x,y\)
\(\left|x-1\right|^{2023}>=0\forall x\)
=>\(\left(2x-y+7\right)^{2022}+\left|x-1\right|^{2023}>=0\forall x,y\)
mà \(\left(2x-y+7\right)^{2022}+\left|x-1\right|^{2023}< =0\forall x,y\)
nên \(\left(2x-y+7\right)^{2022}+\left|x-1\right|^{2023}=0\)
=>\(\left\{{}\begin{matrix}2x-y+7=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=2x+7=9\end{matrix}\right.\)
\(P=x^{2023}+\left(y-10\right)^{2023}\)
\(=1^{2023}+\left(9-10\right)^{2023}\)
=1-1
=0
c: \(\left|x-3\right|>=0\forall x\)
=>\(\left|x-3\right|+2>=2\forall x\)
=>\(\left(\left|x-3\right|+2\right)^2>=4\forall x\)
mà \(\left|y+3\right|>=0\forall y\)
nên \(\left(\left|x-3\right|+2\right)^2+\left|y+3\right|>=4\forall x,y\)
=>\(P=\left(\left|x-3\right|+2\right)^2+\left|y-3\right|+2019>=4+2019=2023\forall x,y\)
Dấu '=' xảy ra khi x-3=0 và y-3=0
=>x=3 và y=3
olm sẽ hướng dẫn em làm bài này như sau:
Bước 1: em giải phương trình tìm; \(x\); y
Bước 2: thay\(x;y\) vào P
(\(x-1\))2022 + |y + 1| = 0
Vì (\(x-1\))2022 ≥ 0 ∀ \(x\); |y + 1| ≥ 0 ∀ y
⇒ (\(x\) - 1)2022 + |y + 1| = 0
⇔ \(\left\{{}\begin{matrix}\left(x-1\right)^{2022}=0\\y+1=0\end{matrix}\right.\)
⇒ \(\left\{{}\begin{matrix}x=1\\y=-1\end{matrix}\right.\) (1)
Thay (1) vào P ta có:
12023.(-1)2022 : )(2.1- 1)2022 + 2023
= 1 + 2023
= 2024
|x - 2| + |y - 1| + (x - y - z)²⁰²² = 0 (1)
Do |x - 2| ≥ 0 với mọi x ∈ R
|y - 1| ≥ 0 với mọi x ∈ R
(x - y - z)²⁰²² ≥ 0 với mọi x ∈ R
(1) ⇒ |x - 2| = |y - 1| = (x - y - z)²⁰²² = 0
*) |x - 2| = 0
x - 2 = 0
x = 2
*) |y - 1| = 0
y - 1 = 0
y = 1
*) (x - y - z)²⁰²² = 0
x - y - z = 0
2 - 1 - z = 0
1 - z = 0
z = 1
⇒ C = 26x - 3y²⁰²² + z²⁰²³
= 26.2 - 3.1²⁰²² + 1²⁰²³
= 52 - 3 + 1
= 50
\(\left(x+3\right)^{2022}+\left(\sqrt{y-2}-1\right)^{2023}=0\) \(\left(ĐKXĐ: y\ge2\right)\)
Xét \(\left(x+3\right)^{2022}\ge0\forall x\)
\(\Rightarrow\left(\sqrt{y-2}-1\right)^{2023}\le0\)
\(\Leftrightarrow\sqrt{y-2}-1\le0\)
\(\Leftrightarrow\sqrt{y-2}\le1\)
\(\Leftrightarrow y-2\le1\)
\(\Rightarrow y\le3\)
\(\Rightarrow2\le y\le3\) mà \(y\in Z\)
\(\Rightarrow\left\{{}\begin{matrix}y=2\Leftrightarrow x=-2\\y=3\Leftrightarrow x=-3\end{matrix}\right.\)
Em không nghĩ câu này đúng. Anh giải thích hộ bạn đó với ạ.
\(\frac{x+1}{2019}+\frac{x+2}{2018}+\frac{x+3}{2017}=\frac{x-1}{2021}+\frac{x-2}{2022}+\frac{x-3}{2023}\)
\(\Leftrightarrow\left(\frac{x+1}{2019}+1\right)+\left(\frac{x+2}{2018}+1\right)+\left(\frac{x+3}{2017}+1\right)=\left(\frac{x-1}{2021}+1\right)+\left(\frac{x-2}{2022}+1\right)+\left(\frac{x-3}{2023}+1\right)\)
\(\Leftrightarrow\left(\frac{x+1+2019}{2019}\right)+\left(\frac{x+2+2018}{2018}\right)+\left(\frac{x+3+2017}{2017}\right)=\left(\frac{x-1+2021}{2021}\right)+\left(\frac{x-2+2022}{2022}\right)+\left(\frac{x-3+2023}{2023}\right)\)
\(\Leftrightarrow\frac{x+2020}{2019}+\frac{x+2020}{2018}+\frac{x+2020}{2017}=\frac{x+2020}{2021}+\frac{x+2020}{2022}+\frac{x+2020}{2023}\)
\(\Leftrightarrow\frac{x+2020}{2019}+\frac{x+2020}{2018}+\frac{x+2020}{2017}-\frac{x+2020}{2021}-\frac{x+2020}{2022}-\frac{x+2020}{2023}=0\)
\(\Leftrightarrow\left(x+2020\right)\left(\frac{1}{2019}+\frac{1}{2018}+\frac{1}{2017}-\frac{1}{2021}-\frac{1}{2022}-\frac{1}{2023}\right)=0\)
Vì \(\frac{1}{2019}+\frac{1}{2018}+\frac{1}{2017}-\frac{1}{2021}-\frac{1}{2022}-\frac{1}{2023}\ne0\)
=> x + 2020 = 0
=> x = -2020
Bài làm :
Ta có :
\(\frac{x+1}{2019}+\frac{x+2}{2018}+\frac{x+3}{2017}=\frac{x-1}{2021}+\frac{x-2}{2022}+\frac{x-3}{2023}\)
\(\Leftrightarrow\left(\frac{x+1}{2019}+1\right)+\left(\frac{x+2}{2018}+1\right)+\left(\frac{x+3}{2017}+1\right)=\left(\frac{x-1}{2021}+1\right)+\left(\frac{x-2}{2022}+1\right)+\left(\frac{x-3}{2023}+1\right)\)
\(\Leftrightarrow\left(\frac{x+1+2019}{2019}\right)+\left(\frac{x+2+2018}{2018}\right)+\left(\frac{x+3+2017}{2017}\right)=\left(\frac{x-1+2021}{2021}\right)+\left(\frac{x-2+2022}{2022}\right)+\left(\frac{x-3+2023}{2023}\right)\)
\(\Leftrightarrow\frac{x+2020}{2019}+\frac{x+2020}{2018}+\frac{x+2020}{2017}=\frac{x+2020}{2021}+\frac{x+2020}{2022}+\frac{x+2020}{2023}\)
\(\Leftrightarrow\frac{x+2020}{2019}+\frac{x+2020}{2018}+\frac{x+2020}{2017}-\frac{x+2020}{2021}-\frac{x+2020}{2022}-\frac{x+2020}{2023}=0\)
\(\Leftrightarrow\left(x+2020\right)\left(\frac{1}{2019}+\frac{1}{2018}+\frac{1}{2017}-\frac{1}{2021}-\frac{1}{2022}-\frac{1}{2023}\right)=0\)
\(\text{Vì : }\frac{1}{2019}+\frac{1}{2018}+\frac{1}{2017}-\frac{1}{2021}-\frac{1}{2022}-\frac{1}{2023}\ne0\)
\(\Rightarrow x+2020=0\Leftrightarrow x=-2020\)
Vậy x=-2020
Lời giải:
Ta thấy: $(x-2022)^2\geq 0$ với mọi $x$
$\Rightarrow (x-2022)^2+2\geq 2$
$\Rightarrow \frac{6}{(x-2022)^2+2}\leq 3$ với mọi $x$ (1)
$|y-2023|\geq 0$ với mọi $y$
$\Rightarrow |y-2023|+3\geq 3$ với mọi $y$ (2)
Từ (1); (2) suy ra để $\frac{6}{(x-2022)^2+2}=|y-2023|+3$ thì:
$\frac{6}{(x-2022)^2+2}=|y-2023|+3=3$
$\Rightarrow x-2022=y-2023=0$
$\Leftrightarrow x=2022; y=2023$