17-X=60:X. Giải giúp mình
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\(a=x+\sqrt{17-x^2}\)
\(a^2=x^2+17-x^2+2x\sqrt{17-x^2}=17+2x\sqrt{17-x^2}\)
\(x\sqrt{17-x^2}=\frac{a^2-17}{2}\)
\(pt\rightarrow a+\frac{a^2-17}{2}=9\Leftrightarrow a^2+2a-35=0\Leftrightarrow\orbr{\begin{cases}a=5\\a=-7\end{cases}}\)
Thay vào, chuyển vế, bình phương ,,,,,,
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\(\dfrac{9}{17}\times\dfrac{21}{13}+\dfrac{9}{17}\times\dfrac{5}{13}-\dfrac{9}{17}\times2\)
\(=\dfrac{9}{17}\times\left(\dfrac{21}{13}+\dfrac{5}{13}-2\right)\)
\(=\dfrac{9}{17}\times\left(\dfrac{26}{13}-2\right)=\dfrac{9}{17}\times\left(2-2\right)\)
\(=\dfrac{9}{17}\times0=0\)
![](https://rs.olm.vn/images/avt/0.png?1311)
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|x+5|+17=20
|x+5|=20-17
|x+5|=3
--> x+5=3
x+5=-3
x= -2
x=-8
nhe duyet di nha olm
/x+5/ -(-17)= 20 <=> /x+5/ =20-17 <=> 2 trường hợp
trường hợp 1: x+5 = 3 => x =-2
trường hợp 2 : x+5 = -3 => x = -8
![](https://rs.olm.vn/images/avt/0.png?1311)
\(17-x=\frac{60}{x}\Leftrightarrow17x-x^2=60\Leftrightarrow17x-x^2-60=0\)
\(\Leftrightarrow-x^2+12x+5x-60=0\Leftrightarrow-x\left(x-12\right)+5\left(x-12\right)=0\)
\(\Leftrightarrow\left(5-x\right)\left(x-12\right)=0\Leftrightarrow\orbr{\begin{cases}5-x=0\\x-12=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=5\\x=12\end{cases}}\)
\(17-x=60:x\)
\(\frac{17-x}{1}=\frac{60}{x}\)
\(x\left(17-x\right)=60.1\)
\(17x-x^2=60\)
\(17x-x^2-60=0\)
\(12x+5x-x^2-60=0\)
\(\left(12x-x^2\right)+\left(5x-60\right)=0\)
\(x\left(12-x\right)+5\left(x-12\right)=0\)
\(x\left(12-x\right)-5\left(12-x\right)=0\)
\(\left(x-5\right)\left(12-x\right)=0\)
\(\Rightarrow\hept{\begin{cases}x-5=0\\12-x=0\end{cases}\Rightarrow\hept{\begin{cases}x=5\\x=12\end{cases}}}\)