Tìm x,y:
a) \(\left|x-3\right|+\left|y-1\right|=0\)
Giải chi tiết dùm mình nha. Thanks
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a: 78x(x-97)-x+97=0
=>(x-97)(78x-1)=0
=>\(\left[{}\begin{matrix}x=97\\x=\dfrac{1}{78}\end{matrix}\right.\)
b: \(\dfrac{2}{3}x\left(x^2-4\right)=0\)
=>\(x\left(x-2\right)\left(x+2\right)=0\)
=>\(\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)
c: \(\left(x+2\right)^2-\left(x-2\right)\left(x+2\right)=0\)
=>\(x^2+4x+4-x^2+4=0\)
=>4x+8=0
=>x+2=0
=>x=-2
\(a,78x\left(x-97\right)-x+97=0\)
\(\Leftrightarrow78x\left(x-97\right)-\left(x-97\right)=0\)
\(\Leftrightarrow\left(x-97\right)\left(78x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-97=0\\78x-1=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=97\\x=\dfrac{1}{78}\end{matrix}\right.\)
\(b,\dfrac{2}{3}x\left(x^2-4\right)=0\)
\(\Leftrightarrow\dfrac{2}{3}x\left(x-2\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{2}{3}x=0\\x-2=0\\x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)
\(c,\left(x+2\right)^2-\left(x-2\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left[\left(x+2\right)-\left(x-2\right)\right]=0\)
\(\Leftrightarrow\left(x+2\right)\left(x+2-x+2\right)=0\)
\(\Leftrightarrow\left(x+2\right)\cdot4=0\)
\(\Leftrightarrow x+2=0\)
\(\Leftrightarrow x=-2\)
\(\dfrac{1}{1.4}+\dfrac{1}{4.7}+\dfrac{1}{7.10}+...+\dfrac{1}{x\left(x+3\right)}=\dfrac{125}{376}\)
\(\Leftrightarrow\dfrac{1}{3}\left(1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+...+\dfrac{1}{x}-\dfrac{1}{x+3}\right)=\dfrac{125}{376}\)
\(\Leftrightarrow\dfrac{1}{3}\left(1-\dfrac{1}{x+3}\right)=\dfrac{125}{376}\left(x\ne0;x\ne-3\right)\)
\(\Leftrightarrow\dfrac{x+3-1}{x+3}=\dfrac{3.125}{376}\Leftrightarrow\dfrac{x+2}{x+3}=\dfrac{3.125.}{376}.\dfrac{\left(x+3\right)}{x+3}\)
\(\Leftrightarrow376\left(x+2\right)=3.125.\left(x+3\right)\)
\(\Leftrightarrow376x+752=375x+1125\)
\(\Leftrightarrow376x-375x=1125-752\Leftrightarrow x=373\left(x\in N^{\cdot}\right)\)
Để olm.vn giúp em nhá:
(\(x-5\))2002 + (2\(x\) + 1)2000 = 0
vì (\(x\) - )2022 ≥ 0 ∀ \(x\)
(2\(x\) + 1)2000 \(\ge\) 0 ∀ \(x\)
⇒ (\(x\) - 5)2002 + (2\(x\) + 1)2000 = 0
⇔ \(\left\{{}\begin{matrix}\left(x-5\right)^{2002}=0\\\left(2x+1\right)^{2000}=0\end{matrix}\right.\)
\(\Rightarrow\) \(\left\{{}\begin{matrix}x-5=0\\2x+1=0\end{matrix}\right.\)
\(\Rightarrow\) \(\left\{{}\begin{matrix}x=5\\2x=-1\end{matrix}\right.\)
⇒ \(\left\{{}\begin{matrix}x=5\\x=-\dfrac{1}{2}\end{matrix}\right.\)
vì - \(\dfrac{1}{2}\) \(\ne\) 5 vậy \(x\in\) \(\varnothing\)
\(\left\{{}\begin{matrix}\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{5}{6}\\\dfrac{\dfrac{2}{3}}{x}+\dfrac{\dfrac{2}{3}}{y}+\dfrac{\dfrac{8}{9}}{y}=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{5}{6}\\\dfrac{\dfrac{2}{3}}{x}+\dfrac{\dfrac{14}{9}}{y}=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{5}{6}\left(1\right)\\\dfrac{2}{3x}+\dfrac{14}{9y}=1\left(2\right)\end{matrix}\right.\)
Nhân cả hai vế (1) cho \(\dfrac{2}{3}\) ta có: \(\left\{{}\begin{matrix}\dfrac{2}{3x}+\dfrac{2}{3y}=\dfrac{5.2}{6.3}\\\dfrac{2}{3x}+\dfrac{14}{9y}=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{2}{3x}+\dfrac{2}{3y}=\dfrac{10}{18}\left(3\right)\\\dfrac{2}{3x}+\dfrac{14}{9y}=1\left(4\right)\end{matrix}\right.\)
Lấy (4) trừ (3) ta có:
\(\dfrac{14}{9y}-\dfrac{2}{3y}=1-\dfrac{10}{18}\)\(\Leftrightarrow\dfrac{8}{9y}=\dfrac{4}{9}\)\(\Leftrightarrow y=2\Rightarrow x=\dfrac{1}{\dfrac{5}{6}-\dfrac{1}{2}}=3\)
Có: \(\left\{{}\begin{matrix}\left|x-3\right|\ge0\forall x\\\left|y-1\right|\ge0\forall y\end{matrix}\right.\)
\(\Rightarrow\left|x-3\right|+\left|y-1\right|\ge0\forall x;y\)
Mà: \(\left|x-3\right|+\left|y-1\right|=0\)
nên: \(\left\{{}\begin{matrix}x-3=0\\y-1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=1\end{matrix}\right.\)