cíuuuuu mình với thanks
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a: \(\Leftrightarrow\left(5x+\dfrac{3}{2}\right):\dfrac{8}{15}=\dfrac{25}{12}-\dfrac{5}{6}=\dfrac{25}{12}-\dfrac{10}{12}=\dfrac{15}{12}=\dfrac{5}{4}\)
\(\Leftrightarrow5x+\dfrac{3}{2}=\dfrac{5}{4}\cdot\dfrac{8}{15}=\dfrac{40}{60}=\dfrac{2}{3}\)
\(\Leftrightarrow5x=\dfrac{2}{3}-\dfrac{3}{2}=\dfrac{4-9}{6}=\dfrac{-5}{6}\)
hay x=-1/6
b: \(\Leftrightarrow\dfrac{1}{4}\left(2-\dfrac{1}{2}x\right)=\dfrac{5}{2}-\dfrac{1}{4}=\dfrac{10}{4}-\dfrac{1}{4}=\dfrac{9}{4}\)
=>2-1/2x=9
=>1/2x=-7
hay x=-14
c: \(\Leftrightarrow\left(x-7\right)^2=144\)
=>x-7=12 hoặc x-7=-12
=>x=19 hoặc x=-5
d: \(\Leftrightarrow4x+2=3x-15\)
hay x=-17
e: =>1/6x=-4
hay x=-24
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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
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cũng dễ thôi mà!!!
a, \(x^2-7x+6=x^2-x-6x+6\)
\(=x\left(x-1\right)-6\left(x-1\right)\)
\(=\left(x-6\right)\left(x-1\right)\)
b, \(|2x+1|-5x=3\)(*)
TH1: \(2x+1\ge0=>x\ge\frac{-1}{2}\)
PT(*) <=> \(2x+1-5x=3=>x=\frac{-2}{3}\)(thỏa mãn)
TH2: \(2x+1< 0=>x< \frac{-1}{2}\)
PT(*) <=> \(-2x-1-5x=3=>x=\frac{4}{7}\)(ko thỏa mãn)
Vậy phương trình có tập nghiệm S=\(\left\{\frac{-2}{3}\right\}\)