B

a) \(M=2022-\left|x-9\right|\le2022\)

\(maxM=2022\Leftrightarrow x=9\)

b) \(N=\left|x-2021\right|+2022\ge2022\)

\(minN=2022\Leftrightarrow x=2021\)

A = (x+5)²⁰²² + | y - 2021| + 2022

vì ( x+5)²⁰²² \(\ge\) 0; 

    |y-2021|   \(\ge\) 0

    2022      = 2022

Cộng vế với vế ta được : A = (x+5)²⁰²²+|y-2021|+2022\(\ge\) 2022

Vậy A(min) = 2022 dấu bằng xảy ra khi : \(\left\{{}\begin{matrix}x+5=0\\y-2021=0\end{matrix}\right.\)=>\(\left\{{}\begin{matrix}x=-5\\y=2021\end{matrix}\right.\)

a: ta có: \(A=x^2-3x+10\)

\(=x^2-2\cdot x\cdot\dfrac{3}{2}+\dfrac{9}{4}+\dfrac{31}{4}\)

\(=\left(x-\dfrac{3}{2}\right)^2+\dfrac{31}{4}>0\forall x\)

b: Ta có: \(B=x^2-5x+2021\)

\(=x^2-2\cdot x\cdot\dfrac{5}{2}+\dfrac{25}{4}+\dfrac{8015}{4}\)

\(=\left(x-\dfrac{5}{2}\right)^2+\dfrac{8015}{4}>0\forall x\)

các bạn giúp mik với. Đề trên kia là \(\sqrt{x}+2021\) nhé! Mik đánh sai 

Đặt A = 5x² + 2y² + 4xy - 2x + 4y + 2022

= (2x² + 4xy + 2y²) + 4(x + y) + 2 + (3x² - 6x + 3) + 2017

= 2(x + y)² + 4(x + y) + 2 + 3(x - 1)² + 2017

= 2(x + y + 1)² + 3(x - 1)² + 2017 \(\ge\)2017

=> Min A = 2017

\(5x^2+2y^2+4xy-2x+4y+2022\)

\(=\left(4x^2+4x+y^2\right)+\left(y^2+4y+4\right)+\left(x^2-2x+1\right)+2017\)

\(=\left(2x+y\right)^2+\left(y+2\right)^2+\left(x-1\right)^2+2017\)

Dấu "=" xảy ra khi \(\hept{\begin{cases}2x+y=0\\y+2=0\\x-1=0\end{cases}\Leftrightarrow\hept{\begin{cases}x=1\\y=-2\end{cases}}}\)

Vậy \(Min_A=2017\Leftrightarrow x=1;y=-2\)

A.

$a^2+4b^2+9c^2=2ab+6bc+3ac$

$\Leftrightarrow a^2+4b^2+9c^2-2ab-6bc-3ac=0$

$\Leftrightarrow 2a^2+8b^2+18c^2-4ab-12bc-6ac=0$

$\Leftrightarrow (a^2+4b^2-4ab)+(a^2+9c^2-6ac)+(4b^2+9c^2-12bc)=0$

$\Leftrightarrow (a-2b)^2+(a-3c)^2+(2b-3c)^2=0$

$\Rightarrow a-2b=a-3c=2b-3c=0$

$\Rightarrow A=(0+1)^{2022}+(0-1)^{2023}+(0+1)^{2024}=1+(-1)+1=1$

B.

$x^2+2xy+6x+6y+2y^2+8=0$

$\Leftrightarrow (x^2+2xy+y^2)+y^2+6x+6y+8=0$

$\Leftrightarrow (x+y)^2+6(x+y)+9+y^2-1=0$

$\Leftrightarrow (x+y+3)^2=1-y^2\leq 1$ (do $y^2\geq 0$ với mọi $y$)

$\Rightarrow -1\leq x+y+3\leq 1$

$\Rightarrow -4\leq x+y\leq -2$

$\Rightarrow 2020\leq x+y+2024\leq 2022$

$\Rightarrow A_{\min}=2020; A_{\max}=2022$

Ko thèm tick cho người ta mà đòi hỏi câu khác ✅