Giup to boi . Ai lam dung to tick nha
Tim x :
l 1/2 + 1/5+ x l = -1/4
l x - 5/3 l < 1/3
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h: =>7x-21-15+5x=11x-5
=>12x-36=11x-5
hay x=31
l: (x+3)(x-4)=0
=>x+3=0 hoặc x-4=0
=>x=-3 hoặc x=4
i: =>5x-30-2x-6=12
=>3x-36=12
hay x=16
m: =>119+27x=8x52
=>27x=297
hay x=11
1 Tìm x
a) 3(2x-1)-5(x+1)- 4 l-5l=0
b) 5 .l3x+1l - 15=4. l 3 x + 1 l + 4
Giup mình vs nhé mình tick cho
\(c)\) \(\left|2x-1\right|-2x=3\)
\(\Leftrightarrow\)\(\left|2x-1\right|=2x+3\)
Ta có : \(\left|2x-1\right|\ge0\)
\(\Rightarrow\)\(2x+3\ge0\)\(\Rightarrow\)\(2x\ge-3\)\(\Rightarrow\)\(x\ge\frac{-3}{2}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}2x-1=2x+3\\2x-1=-2x-3\end{cases}\Leftrightarrow\orbr{\begin{cases}2x-2x=3+1\\2x+2x=-3+1\end{cases}}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}0=4\\4x=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}0=4\left(loai\right)\\x=\frac{-1}{2}\left(tm\right)\end{cases}}}\)
Vậy \(x=\frac{-1}{2}\)
Chúc bạn học tốt ~
\(b)\) \(3\left(2x-1\right)-\left|x-5\right|=7\)
\(\Leftrightarrow\)\(3\left(2x-1\right)-7=\left|x-5\right|\)
\(\Leftrightarrow\)\(6x-3-7=\left|x-5\right|\)
\(\Leftrightarrow\)\(\left|x-5\right|=6x-10\)
Ta có : \(\left|x-5\right|\ge0\)
\(\Rightarrow\)\(6x-10\ge0\)\(\Rightarrow\)\(6x\ge10\)\(\Rightarrow\)\(x\ge\frac{5}{3}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x-5=6x-10\\x-5=10-6x\end{cases}\Leftrightarrow\orbr{\begin{cases}6x-x=-5+10\\x+6x=10+5\end{cases}}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}5x=5\\7x=15\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\left(loai\right)\\x=\frac{15}{7}\left(tm\right)\end{cases}}}\)
Vậy \(x=\frac{15}{7}\)
Chúc bạn học tốt ~
e) \(2^x+2^{x+3}=144\)
\(\Leftrightarrow2^x+2^x.2^3=144\)
\(\Leftrightarrow2^x.\left(1+8\right)=144\)
\(\Leftrightarrow2^x.9=144\)
\(\Rightarrow2^x=144:9=16\)
Ta có :\(2^4=16\Rightarrow x=4\)
l)\(0,2:1\frac{1}{5}=\frac{2}{3}:\left|6x+7\right|\)
\(\Leftrightarrow\frac{2}{3}:\left|6x+7\right|=\frac{1}{6}\)
\(\Rightarrow\left|6x+7\right|=\frac{2}{3}:\frac{1}{6}\)
\(\Rightarrow\left|6x+7\right|=4\)
\(\Rightarrow\orbr{\begin{cases}6x+7=4\\6x+7=-4\end{cases}\Rightarrow\orbr{\begin{cases}6x=-3\\6x=-11\end{cases}\Rightarrow}\orbr{\begin{cases}x=-\frac{1}{2}\\x=-\frac{11}{6}\end{cases}}}\)
a/ \(\left|x-\frac{1}{3}\right|=2\frac{1}{5}\)
\(\left|x-\frac{1}{3}\right|=\frac{11}{5}\)
\(\Rightarrow\left[{}\begin{matrix}x-\frac{1}{3}=\frac{11}{5}\\x-\frac{1}{3}=\frac{-11}{5}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{11}{5}+\frac{1}{3}\\x=\frac{-11}{5}+\frac{1}{3}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{33}{15}+\frac{5}{15}\\x=\frac{-33}{15}+\frac{5}{15}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{38}{15}\\x=\frac{28}{15}\end{matrix}\right.\)
Vậy:
c/
\(\left|x+\frac{1}{4}\right|-\frac{3}{4}=5\%\)
\(\left|x+\frac{1}{4}\right|-\frac{3}{4}=\frac{1}{20}\)
\(\left|x+\frac{1}{4}\right|=\frac{1}{20}+\frac{15}{20}\)
\(\left|x+\frac{1}{4}\right|=\frac{4}{5}\)
\(\Rightarrow\left[{}\begin{matrix}x+\frac{1}{4}=\frac{4}{5}\\x+\frac{1}{4}=\frac{-4}{5}\end{matrix}\right.\)
Bạn tự tính tiếp nhé!
|1/2+1/5+x|=-1/4
|7/10+x|=-1/4
|0,7+x|=-0,25
Vì |0,7+x| > or = 0
-0.25<0
=>x E {rỗng}
|x-5/3| < 1/3
=>x-5/3 < +- 1/3
=>\(\orbr{\begin{cases}x-\frac{5}{3}=\frac{1}{3}=>x=\frac{1}{3}+\frac{5}{3}=\frac{6}{3}=2\\x-\frac{5}{3}=-\frac{1}{3}=>x=-\frac{1}{3}+\frac{5}{3}=\frac{4}{3}\end{cases}}\)
=> x E {2;-4/3}
ko cần