nhà em làm nghề chăn bò còn nếu em hỏi nhà em ở ngoài đòi thì ko ai biết cả

sai rồi

1 nha em xin kiich

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\(x\times3+x\times6+x=125+75.\)

\(x\times3+x\times6+x\times1=200\)

\(x\times\left(3+6+1\right)=200\)

\(x\times10=200\)

\(x=200\div10\)

\(x=20\)

\(x\times3+x\times6+x=125+75\)

\(x\times3+x\times6+x\times1=125+75\)

\(x\times\left(3+6+1\right)=200\)

\(x\times10=200\)

\(x=200\div10\)

\(x=20\)

\(M=4x-x^2+3\\ =-(x^2-4x-3)\\ =-(x^2-4x+4)+7\\ =-(x+2)^2+7 \leq7,\forall x\in \mathbb{R}\quad (\mathrm{vì}-(x+2)^2\leq0)\)

Dấu bằng xảy ra khi và chỉ khi \(-(x+2)^2=0\Leftrightarrow x+2=0 \Leftrightarrow x=-2\). 

Vậy \(\mathrm{Max}M=7\Leftrightarrow x=-2\).

Giải cả cách hộ mk

love nha

mik cũng chúc bạn trung thu vui vẻ

$a)\frac{9}{11}$ và $\frac{13}{15}$

Ta có :

$1-\frac{9}{11}=\frac{2}{11}$

$1-\frac{13}{15}=\frac{2}{15}$

Mà $\frac{2}{11}>\frac{2}{15}$ nên $\frac{9}{11}<\frac{13}{15}$

$b)\frac{19}{15}$ và $\frac{15}{11}$

Ta có :

$\frac{19}{15}-1=\frac{4}{15}$

$\frac{15}{11}-1=\frac{4}{11}$

Mà $\frac{4}{15}<\frac{4}{11}$ nên $\frac{19}{15}<\frac{15}{11}$

$c)\frac{201}{301}$ và $\frac{199}{308}$

Ta có :

$\frac{201}{301}>\frac{199}{301}$

$\frac{199}{308}<\frac{199}{301}$

Vậy $\frac{201}{301}>\frac{199}{308}$

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Theo bài ra ta có : a = 5k + 4

Khi đó : a2 = ( 5k + 4 )2

=> a2 = 25 k2 + 40k + 16

=> a2 = 5 . ( 5k2 + 8k + 3 ) + 1

Suy ra a2 chia cho 5 dư 1 ( ĐPCM )

Đpcm nha