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VN
25 tháng 4 2017
\(x^2+81x+158=0\)
\(\Leftrightarrow x^2+81x+\left(\frac{81}{2}\right)^2-\left(\frac{81}{2}\right)^2+158=0\)
\(\Leftrightarrow\left(x+\frac{81}{2}\right)^2-\frac{5929}{4}=0\)
\(\Leftrightarrow\left(x+\frac{81}{2}\right)^2=\frac{5929}{4}\)
\(\Leftrightarrow\left(x+\frac{81}{2}\right)^2=\left(\frac{77}{2}\right)^2hay\left(x+\frac{81}{2}\right)=\left(-\frac{77}{2}\right)^2\)
\(\Leftrightarrow x+\frac{81}{2}=\frac{77}{2}hayx+\frac{81}{2}=-\frac{77}{2}\)
\(\Leftrightarrow x=-2hayx=-79\)
Vậy: S = {-2;-79}
25 tháng 4 2017
x^2+81x+158=0
<=>x^2+2x+79x+158=0
<=>x(x+2)+79(x+2)=0
<=>(x+2)(x+79)=0
<=>x+2=0 hoặc x+79=0
<=> x=-2 hoặc x= -79
Vậy tập nghiệm của phương trình là S={-79;-2}
H
1
AH
Akai Haruma
Giáo viên
7 tháng 2 2020
Lời giải:
$\frac{x-1001}{1002}+\frac{x-1950}{53}=\frac{x+158}{2161}+\frac{x+193}{2196}$
$\Leftrightarrow \frac{x-1001}{1002}-1+\frac{x-1950}{53}-1=\frac{x+158}{2161}-1+\frac{x+193}{2196}-1$
$\Leftrightarrow \frac{x-2003}{1002}+\frac{x-2003}{53}=\frac{x-2003}{2161}+\frac{x-2003}{2196}$
$\Leftrightarrow (x-2003)\left(\frac{1}{1002}+\frac{1}{53}-\frac{1}{2161}-\frac{1}{2196}\right)=0$
Dễ thấy $\left(\frac{1}{1002}+\frac{1}{53}-\frac{1}{2161}-\frac{1}{2196}\right)\neq 0$ nên $x-2003=0\Rightarrow x=2003$
8 tháng 4 2020
1582+582-116.158
=1582-116.158+582
=1582-2.58.158+582
=(158-58)2=1002=10000
#hoktot<3#
#đề nghị mấy bn lm sau k chép,mik cần công bằng ạ,cảm ơn#
14 tháng 2 2022
1: \(\Leftrightarrow\left(x-3\right)\left(x+3\right)-\left(x-3\right)\left(5x+2\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(-4x+1\right)=0\)
hay \(x\in\left\{3;\dfrac{1}{4}\right\}\)
2: \(\Leftrightarrow\left(x-1\right)\left(x^2+x+1\right)-\left(x-1\right)\left(x^2-2x+16\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x^2+x+1-x^2+2x-16\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(3x-15\right)=0\)
hay \(x\in\left\{1;5\right\}\)
3: \(\Leftrightarrow\left(x-1\right)\left(4x^2-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(2x-1\right)\left(2x+1\right)=0\)
hay \(x\in\left\{1;\dfrac{1}{2};-\dfrac{1}{2}\right\}\)
4: \(\Leftrightarrow x^2\left(x+4\right)-9\left(x+4\right)=0\)
\(\Leftrightarrow\left(x+4\right)\left(x-3\right)\left(x+3\right)=0\)
hay \(x\in\left\{-4;3;-3\right\}\)
5: \(\Leftrightarrow\left[{}\begin{matrix}3x+5=x-1\\3x+5=1-x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=-6\\4x=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=-1\end{matrix}\right.\)
6: \(\Leftrightarrow\left(6x+3\right)^2-\left(2x-10\right)^2=0\)
\(\Leftrightarrow\left(6x+3-2x+10\right)\left(6x+3+2x-10\right)=0\)
\(\Leftrightarrow\left(4x+13\right)\left(8x-7\right)=0\)
hay \(x\in\left\{-\dfrac{13}{4};\dfrac{7}{8}\right\}\)
14 tháng 2 2022
1.
\(\Leftrightarrow\left(x-3\right)\left(x+3\right)=\left(x-3\right)\left(5x-2\right)\)
\(\Leftrightarrow x+3=5x-2\)
\(\Leftrightarrow4x=5\Leftrightarrow x=\dfrac{5}{4}\)
2.
\(\Leftrightarrow\left(x-1\right)\left(x^2+x+1\right)=\left(x-1\right)\left(x^2-2x+16\right)\)
\(\Leftrightarrow x^2+x+1=x^2-2x+16\)
\(\Leftrightarrow3x=15\Leftrightarrow x=5\)
3.
\(\Leftrightarrow4x^2\left(x-1\right)-\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(4x^2-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=\dfrac{1}{2};x=-\dfrac{1}{2}\end{matrix}\right.\)
NH
19 tháng 2 2020
Bài 1:
a) \(\left(m+2\right).3-5=4\)
\(\Leftrightarrow3m+6-5=4\)
\(\Leftrightarrow3m+1=4\)
\(\Leftrightarrow3m=4-1\)
\(\Leftrightarrow3m=3\)
\(\Leftrightarrow m=1\)
Vậy: m = 1
b) \(\left(m-3\right).\left(-2\right)+8=-10\)
\(\Leftrightarrow-2m+6+8=-10\)
\(\Leftrightarrow-2m+14=-10\)
\(\Leftrightarrow-2m=-10-14\)
\(\Leftrightarrow-2m=-24\)
\(\Leftrightarrow m=12\)
Vậy: m = 12
Bài 2:
a) \(\left(x-2\right)^2=9\)
\(\Leftrightarrow\left(x-2\right)^2=3^2\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=3\\x-2=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-1\end{matrix}\right.\)
b) \(\left(x+3\right)^2-0,16=0\)
\(\Leftrightarrow\left(x+3\right)^2=0,16\)
\(\Leftrightarrow\left(x+3\right)^2=\left(0,4\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0,4\\x+3=-0,4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-2,6\\x=-3,4\end{matrix}\right.\)
c) \(x^3=25x\)
\(\Leftrightarrow x^3-25x=0\)
\(\Leftrightarrow x\left(x^2-25\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x^2-25=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\pm5\end{matrix}\right.\)
<=> (0,16-x).158+(98,5+59,5).x=18
<=> (0,16-x).158+158x=18
<=> (0,16-x+x).158=18
<=> 0,16.158=18
<=>25,28=18
=> vô nghiệm