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7 tháng 11 2015

\(\Rightarrow x+7=a+7-\left(a+1\right)\)

\(\Rightarrow x+7=a+7-a-1\)

\(\Rightarrow x+7=6\)

\(\Rightarrow x=-1\)

\(\frac{1}{a+1}-\frac{1}{a+7}=\frac{a+7}{\left(a+1\right)\left(a+7\right)}-\frac{a+1}{\left(a+1\right)\left(a+7\right)}=\frac{6}{\left(a+1\right)\left(a+7\right)}\)

=>x+7=6

=>x=6-7

=>x=-1

vậy x=-1

29 tháng 9 2015

\(\frac{1}{a+1}-\frac{1}{a+7}=\frac{\left(a+7\right)-\left(a+1\right)}{\left(a+1\right)\left(a+7\right)}=\frac{6}{\left(a+1\right)\left(a+7\right)}\)=> x + 7 = 6 => x = -1

28 tháng 12 2015

X=-2,7

 Tick đi,ns cách làm cho

22 tháng 11 2015

=> 2(x-2) =5-a+a+3

=>2x =4+8

=> x =6

a)Ta có:

\(\frac{x-1}{x+2}=\frac{4}{5}\Leftrightarrow5\left(x-1\right)=4\left(x+2\right)\)

\(\Leftrightarrow5x-5=4x+8\)

\(\Leftrightarrow5x-4x=8+5\)

\(\Leftrightarrow x=13\)

b)Ta có:

\(2^{2x+1}+4^{x+3}=2^{2x+1}+2^{2x+6}=2^{2x+1}\left(1+2^5\right)=2^{2x+1}.33=264\Leftrightarrow2^{2x+1}=8=2^3\)\(\Rightarrow2x+1=3\Leftrightarrow2x=2\Leftrightarrow x=1\)

c)Ta có:

\(\frac{x^2}{-8}=\frac{27}{x}\Leftrightarrow x^3=-8.27=-216\Leftrightarrow x=-6\)

d)Ta có:

\(\frac{x+7}{-20}=\frac{-5}{x+7}\Leftrightarrow\left(x+7\right)^2=\left(-20\right)\left(-5\right)=100\Leftrightarrow\left[{}\begin{matrix}x+7=10\\x+7=-10\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-17\end{matrix}\right.\)e)Ta có:

\(\frac{x}{-8}=\frac{2}{-x^3}\Leftrightarrow x.\left(-x^3\right)=-8.2\)

\(\Leftrightarrow-x^4=-16\Leftrightarrow x^4=16\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)

Question 1:Fill the suitable number in the following blank?.\(343=\)_____\(3\)Question 2:The positive value of  such that  \(\left|2x-3\right|+7=16\) is _______Question 3:Given a function \(g\left(x\right)=2\sqrt{x-7}\) . Find the value of \(g\left(11\right)\)?Answer: The value of \(g\left(11\right)\) is ._________Question 4:Find the value of  such that \(0,008=\left(0,2\right)^x\).Answer: . \(x=\)_________Question 5:Given a function\(g\left(x\right)=\frac{2}{3-x}\) . Find the value...
Đọc tiếp

Question 1:
Fill the suitable number in the following blank?
.\(343=\)_____\(3\)

Question 2:
The positive value of  such that  \(\left|2x-3\right|+7=16\) is _______

Question 3:
Given a function \(g\left(x\right)=2\sqrt{x-7}\) . Find the value of \(g\left(11\right)\)?
Answer: The value of \(g\left(11\right)\) is ._________

Question 4:
Find the value of  such that \(0,008=\left(0,2\right)^x\).
Answer: . \(x=\)_________

Question 5:
Given a function\(g\left(x\right)=\frac{2}{3-x}\) . Find the value of .\(g\left(1\right)+g\left(2\right)\)
Answer: The value of \(g\left(1\right)+g\left(2\right)\) is ._______

Question 6:
Suppose that \(\frac{7y-x}{2x+y}=\frac{1}{3}\) then the ratio of  \(x\) to  \(y\)  is .________

Question 7:
If \(x\) is directly proportional to \(y\) with the scaling factor is 8, \(z\)  is directly proportional to \(x\) with the scaling factor is 4.
Then \(z\)  is directly proportional to \(y\) with the scaling factor is______ .

Question 8:
The maximum value of \(A=\frac{6}{2.\left(x-3\right)^2+3}\) is .______

Question 10:
Suppose that\(\frac{7-3x}{5}=\frac{y+4}{3}=\frac{6x-y}{5}\) . Find the ratio of \(y\) to \(x\)
Answer: The ratio of \(y\) to \(x\) is .______________-
(write your answer by decimal in simplest form)

3
6 tháng 1 2016

nói thế nói làm gì bạn ơi

6 tháng 1 2016

you may also be investigated google it.

4 tháng 6 2019

bạn ơi trả lời được câu này kông

( x + 1 ) + ( x - 3 ) + ( x + 5 ) + ............ + ( x +9) = 35