(x-3)^2=9-x^2
Ai giải giúp mình với mình cần gấp
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\(\sqrt{x^2-9}-3\sqrt{x-3}=0\left(đk:x\ge3\right)\)
\(\Leftrightarrow\sqrt{\left(x-3\right)\left(x+3\right)}-3\sqrt{x-3}=0\)
\(\Leftrightarrow\sqrt{x-3}\left(\sqrt{x+3}-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x-3}=0\\\sqrt{x+3}=3\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x+3=9\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=3\left(tm\right)\\x=6\left(tm\right)\end{matrix}\right.\)
\(ĐK:x\le-3;x\ge3\\ PT\Leftrightarrow\sqrt{x-3}\left(\sqrt{x+3}-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-3=0\\\sqrt{x+3}=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x+3=9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\left(tm\right)\\x=6\left(tm\right)\end{matrix}\right.\)
\(\left(-3\sqrt{x}+2\right)\left(x\sqrt{x}+4\sqrt{x}+1\right)\)
\(=-3\sqrt{x}\left(x\sqrt{x}+4\sqrt{x}+1\right)+2\left(x\sqrt{x}+4\sqrt{x}+1\right)\)
\(=-3x^2-12x-3\sqrt{x}+2x\sqrt{x}+8\sqrt{x}+2\)
\(=-3x^2-12x+5\sqrt{x}+2x\sqrt{x}+2\)
\(3\times\left(x-2\right)+9=30\)
\(3\times\left(x-2\right)=30-9\)
\(3\times\left(x-2\right)=21\)
\(x-2=7\)
\(x=9\)
\(3^2+x=81\)
\(\Rightarrow9+x=81\)
\(\Rightarrow x=81-9\)
\(\Rightarrow x=72\)
Vậy \(x=72\)
CHÚC BẠN HỌC TỐT NHÉ
1/2* x+2/3=9/2
1/2 * x = 9/2 - 2/3
1/2 * x= 23/6
x= 23/6 : 1/2
x= 23/6 x 2= 23/3
___
1/2*x-1/3=2/3
1/2*x = 2/3 + 1/3
1/2 * x= 1
x= 1: 1/2
x= 2
____
1/4+3/4:x=3
3/4 : x = 3 - 1/4
3/4 : x= 11/4
x= 11/4 : 3/4
x= 11/3
\(\dfrac{1}{2}\)\(\times\)\(x\) + \(\dfrac{2}{3}\) = \(\dfrac{9}{2}\)
\(\dfrac{1}{2}\)\(\times\)\(x\) = \(\dfrac{9}{2}\) - \(\dfrac{2}{3}\)
\(\dfrac{1}{2}\)\(\times\)\(x\) = \(\dfrac{23}{6}\)
\(x\) = \(\dfrac{23}{6}\):\(\dfrac{1}{2}\)
\(x\) = \(\dfrac{23}{3}\)
\(\dfrac{1}{2}\)\(\times\)\(x\) - \(\dfrac{1}{3}\) = \(\dfrac{2}{3}\)
\(\dfrac{1}{2}\)\(\times\)\(x\) = \(\dfrac{2}{3}\) + \(\dfrac{1}{3}\)
\(\dfrac{1}{2}\times\)\(x\) = 1
\(x\) = 1 : \(\dfrac{1}{2}\)
\(x\) = 2
\(\dfrac{1}{4}\) + \(\dfrac{3}{4}\): \(x\) = 3
\(\dfrac{3}{4}\): \(x\) = 3 - \(\dfrac{1}{4}\)
\(\dfrac{3}{4}\):\(x\) = \(\dfrac{11}{4}\)
\(x\) = \(\dfrac{3}{4}\): \(\dfrac{11}{4}\)
\(x\) = \(\dfrac{3}{11}\)
Vì ( 2x - 4).( 3x + 9 ) = 0
=> 2x - 4 hoặc 3x + 9 = 0
TH1: 2x - 4 = 0
2x = 4
x=2
TH2: 3x + 9 = 0
3x = -9
x = -3
Vậy, x = -3 hoặc 2
\(\left(2x-4\right)\left(3x+9\right)=0\)
\(\orbr{\begin{cases}2x-4=0\\3x+9=0\end{cases}}\)
TH1. \(2x-4=0\)
\(2x=4\)
\(x=2\)
TH2. \(3x+9=0\)
\(3x=9\)
\(x=3\)
Vậy \(x\in\left\{2;3\right\}\)
@Nghệ Mạt
#cua
sorry , em mới học lớp 7 .