Làm hộ mình câu b bài 6 ạ
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NL
Nguyễn Lê Phước Thịnh
CTVHS
18 tháng 2 2021
1) Vì x=25 thỏa mãn ĐKXĐ nên Thay x=25 vào biểu thức \(A=\dfrac{\sqrt{x}-2}{x+1}\), ta được:
\(A=\dfrac{\sqrt{25}-2}{25+1}=\dfrac{5-2}{25+1}=\dfrac{3}{26}\)
Vậy: Khi x=25 thì \(A=\dfrac{3}{26}\)
2) Ta có: \(B=\dfrac{\sqrt{x}-3}{\sqrt{x}+1}+\dfrac{2x+8\sqrt{x}-6}{x-\sqrt{x}-2}\)
\(=\dfrac{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}+\dfrac{2x+8\sqrt{x}-6}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{x-5\sqrt{x}+6+2x+8\sqrt{x}-6}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{3x+3\sqrt{x}}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{3\sqrt{x}\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\)
\(=\dfrac{3\sqrt{x}}{\sqrt{x}-2}\)
DT
Đỗ Thanh Hải
CTVVIP
9 tháng 7 2021
1 She failed to do everything she was supposed to do
2 There is no likelihood that anyone will apply for this post
3 He succeeded in finishing the English test in time
4 There is no likelihood that the situation will improve in the near future
5 There is a chance that you will get what you want there
6 Don't check your answers before answering all the questions
7 I won't give an opinion before thinking this through
8 The judge will decide after hearing all the evidence
9 I won't be able to have a holiday until I save enough money
10 There is little likelihood that my sister will win the first prize in the singing contest
11 He made no reference of his new job when I last spoke to him
9 tháng 7 2021
1 She failed to do everything she was supposed to do
2 There is no likelihood that anyone will apply for this post
3 He succeeded in finishing the English test in time
4 There is no likelihood that the situation will improve in the near future
5 There is a chance that you will get what you want there
6 Don't check your answers before answering all the questions
7 I won't give an opinion before thinking this through
8 The judge will decide after hearing all the evidence
9 I won't be able to have a holiday until I save enough money
10 There is little likelihood that my sister will win the first prize in the singing contest
11 He made no reference of his new job when I last spoke to him
HV
0
NL
Nguyễn Lê Phước Thịnh
CTVHS
24 tháng 12 2021
1: Xét (O) có
DC là tiếp tuyến
DA là tiếp tuyến
Do đó: DC=DA
Xét (O) có
EC là tiếp tuyến
EB là tiếp tuyến
Do đó: EC=EB
Ta có: DC+EC=DE
nên DE=AC+EB
SB
6 tháng 7 2021
mình làm những bài bn chưa lm nhé
9B
10A
bài 2
have repainted
bàii 3
ride - walikking
swimming
watch
HV
0
Bài 6:
a: \(x=\left(2\sqrt3+4\right)\left(4-2\sqrt3\right)=16-12=4\)
Thay x=4 vào E, ta được:
\(E=\frac{2+1}{2}=\frac32\)
b: \(G=\frac{\sqrt{x}+2}{x+2\sqrt{x}+1}-\frac{\sqrt{x}-2}{x-1}\)
\(=\frac{\sqrt{x}+2}{\left(\sqrt{x}+1\right)^2}-\frac{\sqrt{x}-2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)
\(=\frac{\left(\sqrt{x}+2\right)\left(\sqrt{x}-1\right)-\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+1\right)^2\cdot\left(\sqrt{x}-1\right)}\)
\(=\frac{x+\sqrt{x}-2-\left(x-\sqrt{x}-2\right)}{\left(\sqrt{x}+1\right)^2\cdot\left(\sqrt{x}-1\right)}=\frac{2\sqrt{x}}{\left.\left(\sqrt{x}+1\right)^2\cdot\left(\sqrt{x}-1\right)\right.}\)
A=E*G
\(=\frac{\sqrt{x}+1}{\sqrt{x}}\cdot\frac{2\sqrt{x}}{\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)}=\frac{2}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}=\frac{2}{x-1}\)
c: |A+1|>A+1
=>A+1<0
=>\(\frac{2}{x-1}+1<0\)
=>\(\frac{2+x-1}{x-1}<0\)
=>\(\frac{x+1}{x-1}<0\)
=>x-1<0
=>x<1
=>0<x<1