Find the value of x such that :
\(\frac{x+7}{\left(a+1\right)\left(a+7\right)}=\frac{1}{a+1}-\frac{1}{a+7}\)
\(\left(a\ne-7;a\ne-1\right)\)
Answer: x =
( trả lời chứ đừng có mà 8 ở đây nhá mấy má ! )
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Find the value of x such that
\(\frac{x+7}{\left(a+1\right)\left(a+7\right)}=\frac{1}{a+1}-\frac{1}{a+7}\)
(a\(\ne\)-7;-1 )
Answer: x=
find the value of x such that (Tìm x biết ) : \(\frac{x+7}{\left(a+1\right)\left(a+7\right)}=\frac{1}{a+1}-\frac{1}{a+7}\)
( a khác -1; -7 )
\(\frac{1}{a+1}-\frac{1}{a+7}=\frac{a+7}{\left(a+1\right)\left(a+7\right)}-\frac{a+1}{\left(a+1\right)\left(a+7\right)}=\frac{6}{\left(a+1\right)\left(a+7\right)}\)
=>x+7=6
=>x=6-7
=>x=-1
vậy x=-1
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\(\frac{1}{a+1}-\frac{1}{a+7}=\frac{\left(a+7\right)-\left(a+1\right)}{\left(a+1\right)\left(a+7\right)}=\frac{6}{\left(a+1\right)\left(a+7\right)}\)=> x + 7 = 6 => x = -1
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Find the value of such that
\(\frac{x-2}{\left(a+3\right)\left(5-a\right)}=\frac{1}{2\left(a+3\right)}+\frac{1}{2\left(5-a\right)}\) (\(\left(a\ne-3;a\ne5\right)\)
=> 2(x-2) =5-a+a+3
=>2x =4+8
=> x =6
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Find the value of x such that: \(\frac{3\left(x+2\right)}{2x+3}=\frac{7}{8},\left(x\ne-\frac{3}{2}\right)\) . Answer: x = ...
( write your answer by decimal in simplest form )
The value of such that \(3.\left(\frac{1}{7}-\frac{3}{21}+\frac{7}{3}\right)<\frac{x}{2}<\frac{13}{8}.\left(\frac{1}{2}-\frac{1}{6}\right)\)
Answer: x =
given 1<x<3., Find the value of \(A=\frac{\left|x-3\right|}{x-3}-\frac{\left|x-1\right|}{1-x} +\left|x-1\right|+\left|3-x\right|\)
Answer:A=...........
Lời giải:
Vì \(1< x< 3\Rightarrow \left\{\begin{matrix}
|x-3|=|3-x|=3-x\\
|x-1|=x-1\end{matrix}\right.\). Khi đó:
\(A=\frac{|x-3|}{x-3}-\frac{|x-1|}{1-x}+|x-1|+|3-x|\)
\(=\frac{3-x}{x-3}-\frac{x-1}{1-x}+x-1+3-x\)
\(=-1-(-1)+2=2\)
Vậy giá trị của $A$ là $2$
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1.If 2x-y5 then the value of Mleft(x+2y-3right)^2-left(6x+2yright)left(x+2y-3right)+9x^2+6xy+y^22.The free coefficient in the following poly nomaial: left(2x-2right)left(x+1right)left(7-x^2right)is:3.The greatest integer number x such that frac{2x-1}{x-3}-1 0 is:4.How many of the integer n such that satisfy the inequality left(n-3right)^2-left(n-4right)left(n+4right) 43 are less than 3?5.The opposite fraction of frac{x-2}{7-x} is:
Đọc tiếp
1.If 2x-y=5 then the value of M=\(\left(x+2y-3\right)^2-\left(6x+2y\right)\left(x+2y-3\right)+9x^2+6xy\)
\(+y^2\)
2.The free coefficient in the following poly nomaial: \(\left(2x-2\right)\left(x+1\right)\left(7-x^2\right)is:\)
3.The greatest integer number x such that \(\frac{2x-1}{x-3}-1< 0\) is:
4.How many of the integer n such that satisfy the inequality \(\left(n-3\right)^2-\left(n-4\right)\left(n+4\right)< =43\) are less than 3?
5.The opposite fraction of \(\frac{x-2}{7-x}\) is:
Tính giá trị các biểu thức sau:a)Aleft(1+3+...+99+101right).frac{4x-3y}{x-3}.left(x^2-y^2right).left(x^3-y^3right)tại x-1,y-4b)Bfrac{a-10}{b-9}.frac{2a-b}{a+1}với a-b1;ane-1;bne9c) Cfrac{3a-b}{2a+7}+frac{3b-a}{2b-7}với a-b7;ane-frac{7}{2};bnefrac{7}{2}
Đọc tiếp
Tính giá trị các biểu thức sau:
a)\(A=\left(1+3+...+99+101\right).\frac{4x-3y}{x-3}.\left(x^2-y^2\right)\)\(.\left(x^3-y^3\right)\)tại x=-1,y=-4
b)\(B=\frac{a-10}{b-9}.\frac{2a-b}{a+1}\)với \(a-b=1;a\ne-1;b\ne9\)
c) \(C=\frac{3a-b}{2a+7}+\frac{3b-a}{2b-7}\)với \(a-b=7;a\ne-\frac{7}{2};b\ne\frac{7}{2}\)
tìm x biết
a) \(\frac{x-1}{x+2}=\frac{4}{5}\left(x\ne-2\right)\) b)22x+1+4x+3=264 c)\(\frac{x^2}{-8}=\frac{27}{x}\left(x\ne0\right)\) d)\(\frac{x+7}{-20}=\frac{-5}{x+7}\left(x\ne-7\right)\) e)\(\frac{x}{-8}=\frac{2}{-x^3}\left(x\ne0\right)\)
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:
\(\frac{x}{-8}=\frac{2}{-x^3}\Leftrightarrow x.\left(-x^3\right)=-8.2\)
\(\Leftrightarrow-x^4=-16\Leftrightarrow x^4=16\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)