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a) \(\left(x-2018\right)\cdot3=0\)
\(\Leftrightarrow x-2018=0\)
\(\Leftrightarrow x=2018\)
b) \(25\left(x-8\right)=0\)
\(\Leftrightarrow x-8=0\)
\(\Leftrightarrow x=8\)
c) \(25+\left(15+x\right)=75\)
\(\Leftrightarrow15+x=50\)
\(\Leftrightarrow x=35\)
25−(𝑥+[𝑥+(−8)])=0
⇔25−(𝑥+[𝑥−8])=0
⇔25−(𝑥+𝑥−8)=0
⇔25−(2𝑥−8)=0
⇔25−2𝑥+8=0
⇔33−2𝑥=0
⇔−2𝑥+33=0
⇔𝑥=\(\dfrac{33}{2}\)
25−(𝑥+[𝑥+(−8)])=0
⇔25−(𝑥+[𝑥−8])=0
⇔25−(𝑥+𝑥−8)=0
⇔25−(2𝑥−8)=0
⇔25−2𝑥+8=0
⇔33−2𝑥=0
⇔−2𝑥+33=0
⇔𝑥=332
\(a,96-3\left(x+8\right)=42\\ \Rightarrow3\left(x+8\right)=54\\ \Rightarrow x+8=18\\ \Rightarrow x=10.\\ b,15.5\left(x-25\right)-225=0\\ \Rightarrow75\left(x-25\right)-225=0\\ \Rightarrow75\left(x-25\right)=225\\ \Rightarrow x-25=3\\ \Rightarrow x=28.\\ c,250:x+15=25\\ \Rightarrow250:x=10\\ \Rightarrow x=25\\ d,36:\left(x-5\right)=2^2\\ \Rightarrow36:\left(x-5\right)=4\\ \Rightarrow x-5=9\\ \Rightarrow x=14.\\ e,\left[3.\left(70-x\right)+5\right]:2=46\\ \Rightarrow3.\left(70-x\right)+5=92\\ \Rightarrow3\left(70-x\right)=87\\ \Rightarrow70-x=29\\ \Rightarrow x=41.\)
\(a,\left(-31\right).\left(x+7\right)=0\\ \Rightarrow x+7=0\\ \Rightarrow x=-7\\ b,\left(8-x\right).\left(x+13\right)=0\\ \Rightarrow\left[{}\begin{matrix}8-x=0\\x+13=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=8\\x=-13\end{matrix}\right.\\ c,\left(x^2-25\right)\left(3-x\right)=0\\ \Rightarrow\left(x-5\right)\left(x+5\right)\left(3-x\right)=0\\\Rightarrow \left[{}\begin{matrix}x-5=0\\x+5=0\\3-x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\\x=-5\\x=3\end{matrix}\right.\\ d,\left(x-3\right)\left(x^2+4\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-3=0\\x^2+4=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=3\\x^2=-4\left(loại\right)\end{matrix}\right.\\ \Rightarrow x=3\)
\(x\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
Tui mới lớp 1 à....tui ko bít:
/x-13/=5 suy ra x-13 = 5 hoặc -5 suy ra x=....hoặc.....
/-x+8/=/1-8/ suy ra /-x+8/=7 suy ra -x+8=7 hoặc -7 suy ra x=.....hoặc.....
/x+3/+/y-2/=0 suy ra /x+3/=/y-2/=0 suy ra x=....và y=......
THE END...
a) \(\left|x-13\right|=5\)
\(\Rightarrow\orbr{\begin{cases}x-13=5\\x-13=-5\end{cases}\Rightarrow\orbr{\begin{cases}x=18\\x=8\end{cases}}}\)
\(\Rightarrow x\in\left\{8;18\right\}\)
b) (và) \(\left|x+8\right|+3=25\)
\(\left|x+8\right|=22\)
\(\Rightarrow\orbr{\begin{cases}x+8=22\\x+8=-22\end{cases}\Rightarrow\orbr{\begin{cases}x=14\\x=-30\end{cases}}}\)
\(\Rightarrow x\in\left\{-30;14\right\}\)
c) (và) \(\left|-x+8\right|=\left|1-8\right|\)
\(\left|-x+8\right|=7\)
\(\Rightarrow\orbr{\begin{cases}-x+8=7\\-x+8=-7\end{cases}\Rightarrow\orbr{\begin{cases}-x=-1\\-x=-15\end{cases}\Rightarrow}\orbr{\begin{cases}x=1\\x=15\end{cases}}}\)
\(\Rightarrow x\in\left\{1;15\right\}\)
d) (và) Ta có: \(\hept{\begin{cases}\left|x+3\right|\ge0\\\left|y-2\right|\ge0\end{cases}}\)
Dấu "=" xảy ra <=> \(\hept{\begin{cases}\left|x+3\right|=0\\\left|y-2\right|=0\end{cases}\Leftrightarrow\hept{\begin{cases}x=-3\\y=2\end{cases}}}\)
a, bổ sung đề
\(\dfrac{29-x}{21}+1+\dfrac{27-x}{23}+1+\dfrac{25-x}{25}+1+\dfrac{23-x}{27}+1+\dfrac{21-x}{29}+1=0\)
\(\Leftrightarrow\dfrac{50-x}{21}+\dfrac{50-x}{23}+\dfrac{50-x}{25}+\dfrac{50-x}{27}+\dfrac{50-x}{29}=0\)
\(\Leftrightarrow\left(50-x\right)\left(\dfrac{1}{21}+\dfrac{1}{23}+\dfrac{1}{25}+\dfrac{1}{27}+\dfrac{1}{29}\ne0\right)=0\Leftrightarrow x=50\)