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30 tháng 5 2021

 B=\(\left(\dfrac{a+\sqrt{a}}{\sqrt{a}+1}+1\right)\)+\(\left(\dfrac{a-\sqrt{a}}{\sqrt{a}-1}+1\right)\left(x\ge0,x\ne1\right)\)

\(B=\)\(\left[\dfrac{\sqrt{a}\left(\sqrt{a}+1\right)}{\sqrt{a}+1}+1\right]+\left[\dfrac{\sqrt{a}\left(\sqrt{a}-1\right)}{\sqrt{a}-1}+1\right]\)

\(B=\left(\sqrt{a}+1\right)+\left(\sqrt{a}+1\right)=2\sqrt{a}+2\)

b, ĐỂ B=\(\sqrt{a}+1< =>2\sqrt{a}+2=\sqrt{a}+1\)

<=>\(\sqrt{a}=-1\)(vô lí)

vậy a\(\in\phi\)

5 tháng 8 2021

Khó quá trời quá đất,ai biết làm ko?

6 tháng 9 2021

c. \(\left|\dfrac{8}{4}-\left|x-\dfrac{1}{4}\right|\right|-\dfrac{1}{2}=\dfrac{3}{4}\)

\(\Rightarrow\left[{}\begin{matrix}\left|\dfrac{8}{4}-x+\dfrac{1}{4}\right|-\dfrac{1}{2}=\dfrac{3}{4}\\\left|\dfrac{8}{4}+x-\dfrac{1}{4}\right|-\dfrac{1}{2}=\dfrac{3}{4}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\left|\dfrac{9}{4}-x\right|-\dfrac{1}{2}=\dfrac{3}{4}\\\left|\dfrac{7}{4}+x\right|-\dfrac{1}{2}=\dfrac{3}{4}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\left[{}\begin{matrix}\dfrac{9}{4}-x-\dfrac{1}{2}=\dfrac{3}{4}\\x=\dfrac{9}{4}-\dfrac{1}{2}=\dfrac{3}{4}\end{matrix}\right.\\\left[{}\begin{matrix}\dfrac{7}{4}+x-\dfrac{1}{2}=\dfrac{3}{4}\\-\dfrac{7}{4}-x-\dfrac{1}{2}=\dfrac{3}{4}\end{matrix}\right.\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\left[{}\begin{matrix}x=1\\x=\dfrac{7}{2}\end{matrix}\right.\\\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=-3\end{matrix}\right.\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=1\\x=\dfrac{7}{2}\\x=-3\end{matrix}\right.\) 

Ở nơi x=9/4-1/2 là x-9/4-1/2 nha

 

 

6 tháng 9 2021

a. -1,5 + 2x = 2,5

<=> 2x = 2,5 + 1,5

<=> 2x = 4

<=> x = 2

b. \(\dfrac{3}{2}\left(x+5\right)-\dfrac{1}{2}=\dfrac{4}{3}\)

<=> \(\dfrac{3}{2}x+\dfrac{15}{2}-\dfrac{1}{2}=\dfrac{4}{3}\)

<=> \(\dfrac{9x}{6}+\dfrac{45}{6}-\dfrac{3}{6}=\dfrac{8}{6}\)

<=> 9x + 45 - 3 = 8

<=> 9x = 8 + 3 - 45

<=> 9x = -34

<=> x = \(\dfrac{-34}{9}\)

26 tháng 12 2021

Bài 2: 

b: f(0)=5

f(-1)=8

f(-3)=14

29 tháng 12 2021

thank bn

19 tháng 2 2022

=2001

24 tháng 4 2022

a. f(\(\dfrac{-1}{2}\)) = \(4.\left(\dfrac{-1}{2}\right)^2+3.\left(\dfrac{-1}{2}\right)-2\) 

               = \(4.\dfrac{1}{4}-\left(\dfrac{-3}{2}\right)-\dfrac{4}{2}\)

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

               = \(\dfrac{1}{2}\)

 

     

6 tháng 9 2021

C

1 cooking 

2 listening

3 reading

4 playing

5 cycling

1 People collect a lot of things such as stamps, milk bottle labels, comic books as well as car toys

2 She is 20 years old

3 She is a hairdresser

4 It is collecting candy shells

5 Her friends and relatives

B

1 F

2 F

3 F

4 F

5 T