(2x-7)2019=(2x-7)2017
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=>(2x-7)^2017[(2x-7)^2-1]=0
=>(2x-7)(2x-8)(2x-6)=0
hay \(x\in\left\{3;3.5;4\right\}\)
\(\Leftrightarrow\left(2x-3\right)\left(2x-\dfrac{7}{2}\right)\left(2x-\dfrac{5}{2}\right)=0\)
\(\Leftrightarrow x\in\left\{\dfrac{3}{2};\dfrac{7}{4};\dfrac{5}{4}\right\}\)
|2x+2017|=2019
=>\(|^{2x+2017=2019}_{2x+2017=-2019}\)
=>\(|^{2x=2019-2017}_{2x=-2019-2017}\)
=>\(|^{2x=2}_{2x=-4036}\)
=>\(|^{x=2:2}_{x=-4036:2}\)
=>\(|^{x=1}_{x=-2018}\)
Vậy x\(\in\left\{1;-2018\right\}\)
Chúc bn học tốt!
|2x + 2017|= 2019
\(\Rightarrow\)2x + 2017 = 2019 & 2x + 2017 = -2019
TH1: 2x + 2017 = 2019
2x = 2019 - 2017
2x = 2
x = 2 ÷ 2
x = 1
TH2: 2x + 2017 = -2019
2x = -2019 - 2017
2x = - 4036
x = -4036 ÷ 2
x = - 2018
Vây x \(\in\){ 1 ; -2018}
\(\left(7^{2017}-7^{2018}+7^{2019}\right):7^{2017}\)
\(=7^{2017}\left(1-7+7^2\right):7^{2017}\)
\(=1-7+7^2\)
\(=1-7+49\)
\(=53\)
Nhận thấy vế trái luôn dương nên \(x-2020\ge0\Leftrightarrow x\ge2020\)
Với \(x\ge2020\Rightarrow\left\{{}\begin{matrix}x-2017\ge0\\2x-2018\ge0\\3x-2019\ge0\end{matrix}\right.\)
PT trở thành: \(x-2017+2x-2018+3x-2019=x-2020\)
Hay kết hợp với điều kiện \(x=\dfrac{4034}{5}\) suy ra PT đã cho vô nghiệm
Đặt \(2017-x=m,2019-x=n\)
\(\rightarrow m+n=2x-4036\)
Phương trình ban đầu trở thành :
\(m^3+n^3=\left(m+n\right)^3\)
\(\rightarrow3mn.\left(m+n\right)^3=0\)
\(\rightarrow\left(2017-x\right)\left(2019-x\right)\left(2x-4036\right)=0\)
\(\rightarrow\left[{}\begin{matrix}x=2017\\x=2018\\x=2019\end{matrix}\right.\)
Vậy \(S=\left\{2017;2018;2019\right\}\)
(2017-X)3+(2019-X)3+(2X-4036)3=0
<=>(2017-x).(2018-x).(2019-x)=0
<=>x=2017
x=2018
x=2019
#YQ
\(\Leftrightarrow\left(2x-1\right)\left(...\right)=0\Rightarrow x=\frac{1}{2}\)
\(\frac{2x-1}{2020}-\frac{2x-1}{2019}+\frac{2x-1}{2018}=\frac{2x-1}{2017}-\frac{2x-1}{2016}\\ \Leftrightarrow\frac{2x-1}{2020}-\frac{2x-1}{2019}+\frac{2x-1}{2018}-\frac{2x-1}{2017}+\frac{2x-1}{2016}=0\\ \Leftrightarrow\left(2x-1\right)\left(\frac{1}{2020}-\frac{1}{2019}+\frac{1}{2018}-\frac{1}{2017}+\frac{1}{2016}\right)=0\)
mà \(\frac{1}{2020}-\frac{1}{2019}+\frac{1}{2018}-\frac{1}{2017}+\frac{1}{2016}\ne0\)
thì \(2x-1=0\\ \Leftrightarrow2x=1\\ \Leftrightarrow x=\frac{1}{2}\)
vậy \(x=\frac{1}{2}\)
x = 4
\(\Leftrightarrow\left(2x-7\right)^{2017}\left[\left(2x-7\right)^2-1\right]=0\)
=>(2x-7)(2x-6)(2x-8)=0
hay \(x\in\left\{3;\dfrac{7}{2};4\right\}\)