Rút gọn P : P= [x/(x+2)(x-2) + 1/x+2 - 2/x-2 ] : ( 1- x/x+2 )
K
Khách
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5 tháng 5 2021
Câu 1:
Sửa đề: \(B=\left(\dfrac{x}{x+3\sqrt{x}}+\dfrac{1}{\sqrt{x}+3}\right):\left(1-\dfrac{2}{\sqrt{x}}+\dfrac{6}{x+3\sqrt{x}}\right)\)
Ta có: \(B=\left(\dfrac{x}{x+3\sqrt{x}}+\dfrac{1}{\sqrt{x}+3}\right):\left(1-\dfrac{2}{\sqrt{x}}+\dfrac{6}{x+3\sqrt{x}}\right)\)
\(=\left(\dfrac{x}{\sqrt{x}\left(\sqrt{x}+3\right)}+\dfrac{1}{\sqrt{x}+3}\right):\left(\dfrac{x+3\sqrt{x}-2\left(\sqrt{x}+3\right)+6}{\sqrt{x}\left(\sqrt{x}+3\right)}\right)\)
\(=\dfrac{\sqrt{x}+1}{\sqrt{x}+3}:\dfrac{x+3\sqrt{x}-2\sqrt{x}-6+6}{\sqrt{x}\left(\sqrt{x}+3\right)}\)
\(=\dfrac{\sqrt{x}+1}{\sqrt{x}+3}\cdot\dfrac{\sqrt{x}\left(\sqrt{x}+3\right)}{x+\sqrt{x}}\)
\(=\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}\left(\sqrt{x}+1\right)}=1\)
5 tháng 5 2021
Câu 3:
Ta có: \(Q=\left(\dfrac{a}{a-2\sqrt{a}}+\dfrac{a}{\sqrt{a}-2}\right):\dfrac{\sqrt{a}+1}{a-4\sqrt{a}+4}\)
\(=\left(\dfrac{a}{\sqrt{a}\left(\sqrt{a}-2\right)}+\dfrac{a}{\sqrt{a}-2}\right):\dfrac{\sqrt{a}+1}{\left(\sqrt{a}-2\right)^2}\)
\(=\dfrac{a+\sqrt{a}}{\sqrt{a}-2}\cdot\dfrac{\sqrt{a}-2}{\sqrt{a}+1}\cdot\dfrac{\sqrt{a}-2}{1}\)
\(=\sqrt{a}\left(\sqrt{a}-2\right)\)
\(=a-2\sqrt{a}\)
DN
0
TT
1
28 tháng 6 2015
\(\left(x+1\right)\left(x+2\right)\left(x^2+4\right)\left(x-1\right)\left(x^2+1\right)\left(x-2\right)=\left(x+1\right)\left(x-1\right)\left(x+2\right)\left(x-2\right)\left(x^2+4\right)\left(x^2+1\right)\)
\(=\left(x^2-1\right)\left(x^2+1\right)\left(x^2+4\right)\left(x^2-4\right)=\left(x^4-1\right)\left(x^4-16\right)\)
M
3
29 tháng 9 2019
(x + 1)^4 - 6(x + 1)^2 - (x^2 - 2)(x^2 + 2)
= (x^2 + 2x + 1)(x^2 + 2x + 1) - 6(x^2 + 2x + 1) - (x^2 - 2)(x^2 + 2)
= x^2.(x^2 + 2x + 1) + 2x.(x^2 + 2x + 1) + x^2 + 2x + 1 - (x^2 - 2)(x^2 + 2)
= x^4 + 2x^3 + x^2 + 2x^3 + 4x^2 + 2x + x^2 + 2x + 1 - 6x^2 - 12x - 6 - x^2 + 2^2
= 4x^3 - 8x - 1
29 tháng 9 2019
\(\left(x+1\right)^4-6\left(x+1\right)^2-\left(x^2-2\right)\left(x^2+2\right)\)
\(=\left(x^2+2x-5\right)\left(x^2+2x+1\right)-x^4+2\)
\(=x^4+2x^3+x^2+2x^3+4x^2+2x-5x^2-10x-5-x^4+4\)
\(=4x^3-8x-1\)
27 tháng 10 2021
Bài 1:
a: \(Q=\left(\dfrac{\sqrt{x}+2}{x+2\sqrt{x}+1}-\dfrac{\sqrt{x}-2}{x-1}\right)\left(x+\sqrt{x}\right)\)
\(=\dfrac{x+\sqrt{x}-2-x+\sqrt{x}+2}{\left(\sqrt{x}+1\right)^2\cdot\left(\sqrt{x}-1\right)}\cdot\sqrt{x}\left(\sqrt{x}+1\right)\)
\(=\dfrac{2x}{x-1}\)
18 tháng 2 2021
Bạn vào biểu tượng \(\Sigma\) để nhập biểu thức cho chính xác nhé
N
1
TH
9 tháng 7 2017
a) (x+1)(x^2-x+1)-x^3
= x^3+1 - x^3 =1
b) (x-2)^2 -x(x+2)
= x^2 -4x+4-x^2-2x
=-6x+4
=-2(3x-2)
\(P=\left(\frac{x}{\left(x+2\right)\left(x-2\right)}+\frac{1}{x+2}-\frac{2}{x-2}\right):\left(1-\frac{x}{x+2}\right)\)
\(P=\left(\frac{x}{\left(x+2\right)\left(x-2\right)}+\frac{1\cdot\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}-\frac{2\cdot\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}\right):\left(\frac{1\cdot\left(x+2\right)}{x+2}-\frac{x}{x+2}\right)\)
\(P=\frac{x+x-2-2x-4}{\left(x+2\right)\left(x-2\right)}:\frac{x+2-x}{x+2}\)
\(P=\frac{-6}{\left(x+2\right)\left(x-2\right)}:\frac{2}{x+2}\)
\(P=\frac{-6}{\left(x+2\right)\left(x-2\right)}\cdot\frac{x+2}{2}\)
\(P=\frac{-3}{x-2}.\)