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Pham Trong Bach
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Cao Minh Tâm
11 tháng 4 2018 lúc 14:27

Ta có:

satoh nguyễn
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Trần Việt Linh
30 tháng 7 2016 lúc 20:15

b) \(4x-\sqrt{8}+\frac{\sqrt{x^3+2x^2}}{\sqrt{x+2}}\)

\(=4x-\sqrt{8}+\frac{\sqrt{x^2\left(x+2\right)}}{x+2}\)

\(=4x-\sqrt{8}+\frac{x\left(x+2\right)}{x+2}\)

\(=4x-\sqrt{8}+x\)

\(=5x-\sqrt{8}\)

Với \(x=-\sqrt{2}\) ta có:

  \(5x-\sqrt{8}=5\cdot\left(-\sqrt{2}\right)-\sqrt{4\cdot2}=-5\sqrt{2}-2\sqrt{2}=-7\sqrt{2}\)

đặng diễm quỳnh
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ngọc nguyễn
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Đỗ Tuệ Lâm
5 tháng 2 2022 lúc 19:41

biểu thức lỗi ròi á

Nguyễn Lê Phước Thịnh
5 tháng 2 2022 lúc 19:53

bạn ghi lại đề đi bạn

Hùng Chu
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Huỳnh Thị Thanh Ngân
20 tháng 6 2021 lúc 8:50

a)

A=\(\left(\dfrac{x+1}{x-1}-\dfrac{x-1}{x+1}\right)\div\dfrac{2x}{5x-5}\)

\(\Leftrightarrow\left(\dfrac{x+1}{x-1}-\dfrac{x-1}{x+1}\right)\div\dfrac{2x}{5\left(x-1\right)}\)

ĐKXĐ: \(\left\{{}\begin{matrix}x-1\ne0\\x+1\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0+1\\x=0-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)

MTC: 5(x-1)(x+1)

\([\dfrac{5\left(x+1\right)\left(x+1\right)}{5\left(x-1\right)\left(x+1\right)}-\dfrac{5\left(x-1\right)\left(x-1\right)}{5\left(x-1\right)\left(x+1\right)}]\div\dfrac{2x\left(x+1\right)}{5\left(x-1\right)\left(x+1\right)}\)

\(\Rightarrow[5\left(x+1\right)\left(x+1\right)-5\left(x-1\right)\left(x-1\right)]\div2x\left(x+1\right)\)

\(\Leftrightarrow[5\left(x+1\right)^2-5\left(x-1\right)^2]\div2x^2+2x\)

\(\Leftrightarrow[5\left(x^2+2x+1\right)-5\left(x^2-2x+1\right)]\div2x^2+2x\)

\(\Leftrightarrow(5x^2+10x+5-5x^2+10x-5)\div2x^2+2x\)

\(\Leftrightarrow20x\div\left(2x^2+2x\right)\)

\(\Leftrightarrow10x+10\)

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(x+1)2+6−(x−1)(x+3)2(x−1)(x+1)⋅2⋅2(x2−1)5" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline; float:none; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax">(x+1)2+6−(x−1)(x+3)2(x−1)(x+1)⋅2⋅2(x2−1)5

(x+1)2+6−(x2+3x−x−3)(x−1)(x+1)⋅2(x−1)(x+1)5" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline; float:none; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax">(x+1)2+6−(x2+3x−x−3)(x−1)(x+1)⋅2(x−1)(x+1)5

25" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline; float:none; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax">25

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25" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline; float:none; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax">25

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c) tự làm, đkxđ: x1;x1

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nguyễn hải đăng
19 tháng 12 2019 lúc 21:50

ê k bn với mk ik

😘 😘 😘 😘

Loan Tran
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Toru
22 tháng 12 2023 lúc 19:57

a) ĐKXĐ: \(x\ne0;x\ne-2\)

b) \(S=\dfrac{\left(x+2\right)^2}{x}\cdot\left(1-\dfrac{x^2}{x+2}\right)-\dfrac{x^2+6x+4}{x}\)

\(=\dfrac{\left(x+2\right)^2}{x}\cdot\dfrac{x+2-x^2}{x+2}-\dfrac{x^2+6x+4}{x}\)

\(=\dfrac{\left(x+2\right)\left(x+2-x^2\right)}{x}-\dfrac{x^2+6x+4}{x}\)

\(=\dfrac{x^2+2x-x^3+2x+4-2x^2-x^2-6x-4}{x}\)

\(=\dfrac{-x^3-2x^2-2x}{x}\)

\(=\dfrac{x\left(-x^2-2x-2\right)}{x}\)

\(=-x^2-2x-2\)

Với \(x=0\Rightarrow\) loại

Với \(x=1\), thay vào \(S\) ta được

\(S=-1^2-2\cdot1-2=-5\)

c) Có: \(S=-x^2-2x-2\)

\(=-\left(x^2+2x+2\right)\)

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

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

Ta thấy: \(\left(x+1\right)^2\ge0\forall x\ne0;x\ne-2\)

\(\Rightarrow-\left(x+1\right)^2\le0\forall x\ne0;x\ne-2\)

\(\Rightarrow S=-\left(x+1\right)^2-1\le-1\forall x\ne0;x\ne-2\)

Dấu \("="\) xảy ra khi: \(x+1=0\Leftrightarrow x=-1\left(tmdk\right)\)

\(\text{#}\mathit{Toru}\)

Thuc Tran
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Gaming DemonYT
21 tháng 2 2021 lúc 15:00

A xác định khi 5x-10 ≠0 <=> X ≠ 2b) A = x²-4x+4/5x-10= (x-2)²/5(x-2)= x-2/5c) x= -2018<=> A = -2018-2/5= -2020/5 = -404

Chúc bạn học tốt

Nguyễn Lê Phước Thịnh
22 tháng 2 2021 lúc 22:55

a) ĐKXĐ: \(x\ne2\)

b) Ta có: \(A=\dfrac{x^2-4x+4}{5x-10}\)

\(=\dfrac{\left(x-2\right)^2}{5\left(x-2\right)}\)

\(=\dfrac{x-2}{5}\)

Nguyễn Phạm Công Viễn
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Nguyễn Lê Phước Thịnh
31 tháng 12 2021 lúc 14:13

a: ĐKXĐ: \(x\notin\left\{2;-2\right\}\)