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Câu này tớ giải hơn 10 lần rồi cậu ( ko xàm :)
\(\frac{x+2}{98}+\frac{x+4}{96}=\frac{x+6}{94}+\frac{x+8}{92}\)
\(\Leftrightarrow\left(\frac{x+2}{98}+1\right)+\left(\frac{x+4}{96}+1\right)=\left(\frac{x+6}{94}+1\right)+\left(\frac{x+8}{92}+1\right)\)
\(\Leftrightarrow\left(x+100\right)\left(\frac{1}{98}+\frac{1}{96}-\frac{1}{94}-\frac{1}{92}\right)=0\)
Vì \(\frac{1}{98}+\frac{1}{96}-\frac{1}{94}-\frac{1}{92}\ne0\)
Do đó \(x+100=0\Leftrightarrow x=-100\)
Vậy pt có nghiệm : x=-100
Ta có : \(\frac{x+2}{98}+\frac{x+4}{96}=\frac{x+6}{94}+\frac{x+8}{92}\)
=> \(\frac{x+2}{98}+1+\frac{x+4}{96}+1=\frac{x+6}{94}+1+\frac{x+8}{92}+1\)
=> \(\frac{x+100}{98}+\frac{x+100}{96}=\frac{x+100}{94}+\frac{x+100}{92}\)
=> \(\frac{x+100}{98}+\frac{x+100}{96}-\frac{x+100}{94}-\frac{x+100}{92}=0\)
=> \(\left(x+100\right)\left(\frac{1}{98}+\frac{1}{96}-\frac{1}{94}-\frac{1}{92}\right)=0\)
Vì \(\frac{1}{98}+\frac{1}{96}-\frac{1}{94}-\frac{1}{92}\ne0\)
=> x + 100 = 0
=> x = - 100
Vậy x = - 100
Điều kiện: \(x\ne2\)
Pt: \(\Leftrightarrow2^{\dfrac{3x}{x+2}}=2^2.3^{4-x}\Leftrightarrow3^{\dfrac{x-4}{x+2}}=3^{4-x}\)
\(\Leftrightarrow\dfrac{x-4}{x+2}\log_32=4-x\)
\(\Leftrightarrow\left(x-4\right)\left(x+2+\log_32\right)=0\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-2-\log_32\end{matrix}\right.\)
Ta có: \(\left|x+1\right|+3\left|x-1\right|=x+2+\left|x\right|+2\left|x-2\right|\)
=>\(\left|x+1\right|-\left|x\right|+3\left|x-1\right|-2\left|x-2\right|=x+2\) (1)
TH1: x<-1
=>x+1<0; x<0; x-1<0; x-2<0
(1) sẽ trở thành:
-x-1-(-x)+3(-x+1)-2(-x+2)=x+2
=>-x-1+x-3x+3+2x-4=x+2
=>-x-2=x+2
=>-2x=4
=>x=-2(nhận)
TH2: -1<=x<0
=>x+1>=0; x<0; x-1<0; x-2<0
(1) sẽ trở thành:
x+1-(-x)+3(-x+1)-2(-x+2)=x+2
=>x+1+x-3x+3+2x-4=x+2
=>x=x+2
=>0=2(vô lý)
TH3: 0<=x<1
=>x+1>0; x>=0; x-1<0; x-2<0
(1) sẽ trở thành:
x+1-(x)+3(-x+1)-2(-x+2)=x+2
=>1-3x+3+2x-4=x+2
=>-x=x+2
=>-2x=2
=>x=-1(loại)
TH4: 1<=x<2
=>x+1>0; x>0; x-1>=0; x-2<0
(1) sẽ trở thành:
x+1-x+3(x-1)-2(-x+2)=x+2
=>1+3x-3+2x-4=x+2
=>5x-6=x+2
=>4x=8
=>x=2(loại)
TH5: x>=2
=>x+1>0; x>0; x-1>0; x-2>=0
(1) sẽ trở thành:
x+1-x+3(x-1)-2(x-2)=x+2
=>1+3x-3-2x+4=x+2
=>x+2=x+2(luôn đúng)
=>x>=2
Vậy: x>=2 hoặc x=-2
\(\frac{x+2}{98}+\frac{x+4}{96}=\frac{x+6}{94}+\frac{x+8}{92}\)
\(\Leftrightarrow\left(\frac{x+2}{98}+1\right)+\left(\frac{x+4}{96}+1\right)=\left(\frac{x+6}{94}+1\right)+\left(\frac{x+8}{92}+1\right)\)
\(\Leftrightarrow\frac{100+x}{98}+\frac{100+x}{96}-\frac{100+x}{94}-\frac{100+x}{92}=0\)
\(\Rightarrow\left(100+x\right)\left(\frac{1}{98}+\frac{1}{96}+\frac{1}{94}+\frac{1}{92}\right)=0\)
Vì \(\frac{1}{98}+\frac{1}{96}+\frac{1}{94}+\frac{1}{92}\ne0\)
\(\Rightarrow100+x=0\)
\(\Rightarrow x=-100\)
\(\frac{x+2}{98}+\frac{x+4}{96}=\frac{x+6}{94}+\frac{x+8}{92}\)
\(\Leftrightarrow\frac{x+2}{98}+1+\frac{x+4}{96}+1=\frac{x+6}{94}+1+\frac{x+8}{92}+1\)
\(\Leftrightarrow\frac{x+100}{98}+\frac{x+100}{96}=\frac{x+100}{94}+\frac{x+100}{92}\)
\(\Leftrightarrow\frac{x+100}{98}+\frac{x+100}{96}-\frac{x+100}{94}-\frac{x+100}{92}=0\)
\(\Leftrightarrow\left(x+100\right)\left(\frac{1}{98}+\frac{1}{96}-\frac{1}{94}-\frac{1}{92}\right)=0\)
Vì \(\frac{1}{98}< \frac{1}{96}< \frac{1}{94}< \frac{1}{92}\)nên \(\left(\frac{1}{98}+\frac{1}{96}-\frac{1}{94}-\frac{1}{92}\right)< 0\)
Vậy \(x+100=0\Leftrightarrow x=-100\)
`#` `\text{dkhanhqlv}`
`2x^3=x^2+2x-1`
`<=>2x^3-x^2-2x+1=0`
`<=>(2x^3-2x)-(x^2-1)=0`
`<=>2x(x^2-1)-(x^2-1)=0`
`<=>(x^2-1)(2x-1)=0`
`<=>(x+1)(x-1)(2x-1)=0`
`<=>x+1=0` hoặc `x-1=0` hoặc `2x-1=0`
`@TH1:x+1=0<=>x=-1`
`@TH2:x-1=0<=>x=1`
`@TH3:2x-1=0<=>x=0,5`
Vậy tập nghiệm của phương trình đã cho là `S={-1;1;0,5}`
2x^3 = x^2 + 2x - 1
=>2x3 - x2 -2x +1=(x-1).(x+1).(2x-1)
=>x-1=0
=>x=-1
=>x=1
=>x=1/2
8(x-1)-4=6(x+2)-2
8x-8-4=6x+12-2
8x-6x=12-2+8+4
2x=22
x=11
<=> 8x-8-4=6x+12-12
<=> 8x-6x=12-12+8+4
<=> 2x=12
<=> x=6