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a ) Ta có : 4(x - 5) - 3(x + 7) = -19
<=> 4x - 20 - 3x - 21 = -19
=> x - 41 = -19
=> x = -19 + 41
=> x = 22
b) Ta có " 7(x - 3) - 5(3 - x) = 11x - 5
<=> 7x - 21 - 15 + 5x = 11x - 5
<=> 12x - 36 = 11x - 5
=> 12x - 11x = -5 + 36
=> x = 31
a) \(2\left(x-5\right)-3\left(x+7\right)=14\)
\(\Leftrightarrow2x-10-3x-21=14\)
\(\Leftrightarrow-x-31=14\)
\(\Leftrightarrow-x=45\Leftrightarrow x=-45\)
b) \(5\left(x-6\right)-2\left(x+3\right)=12\)
\(\Leftrightarrow5x-30-2x-6=12\)
\(\Leftrightarrow3x-36=12\)
\(\Leftrightarrow3x=48\Leftrightarrow x=16\)
c) \(3\left(x-4\right)-\left(8-x\right)=12\)
\(\Leftrightarrow3x-12-8+x=12\)
\(\Leftrightarrow4x-20=12\)
\(\Leftrightarrow4x=32\Leftrightarrow x=8\)
d) \(-7\left(3x-5\right)+2\left(7x-14\right)=28\)
\(\Leftrightarrow-21x+35+14x-28=28\)
\(\Leftrightarrow-7x+35=0\Leftrightarrow x=5\)
1) \(x-\left|1\frac{1}{6}\right|=\frac{5}{21}\)
\(\Rightarrow x-\frac{5}{21}=\left|1\frac{1}{6}\right|\)
\(\Rightarrow x-\frac{5}{21}=\frac{7}{6}\)
\(\Rightarrow x=\frac{7}{6}+\frac{5}{21}=\frac{49}{42}+\frac{10}{42}=\frac{59}{42}\)
2) \(x+\left|-1\frac{2}{3}\right|=\left|-\frac{3}{4}\right|\)
\(\Rightarrow x+\left|-1\frac{2}{3}\right|=\frac{3}{4}\)
\(\Rightarrow x-\frac{3}{4}=-\left|-1\frac{2}{3}\right|\)
\(\Rightarrow x-\frac{3}{4}=-1\frac{2}{3}\)
\(\Rightarrow x-\frac{3}{4}=-\frac{5}{3}\)
\(\Rightarrow x=-\frac{5}{3}+\frac{3}{4}=-\frac{11}{12}\)
3) \(\left|x-\frac{1}{3}\right|=\frac{5}{2}\)
\(\Rightarrow\left[{}\begin{matrix}x-\frac{1}{3}=\frac{5}{2}\\x-\frac{1}{3}=-\frac{5}{2}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{5}{2}+\frac{1}{3}=\frac{17}{6}\\x=-\frac{5}{2}+\frac{1}{3}=-\frac{13}{6}\end{matrix}\right.\)
4) \(\left|x+\frac{2}{3}\right|=0\)
\(\Rightarrow x+\frac{2}{3}=0\)
\(\Rightarrow x=0-\frac{2}{3}=-\frac{2}{3}\)
5) \(\left|x+2\right|=\frac{1}{3}-\frac{1}{5}\)
\(\Rightarrow\left|x+2\right|=\frac{2}{15}\)
\(\Rightarrow\left[{}\begin{matrix}x+2=\frac{2}{15}\\x+2=-\frac{2}{15}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{2}{15}-2=-\frac{28}{15}\\x=-\frac{2}{15}-2=-\frac{32}{15}\end{matrix}\right.\)
6) \(\left|x-4\right|=\frac{1}{5}-\left(\frac{1}{2}-\frac{5}{4}\right)\)
\(\Rightarrow\left|x-4\right|=\frac{19}{20}\)
\(\Rightarrow\left[{}\begin{matrix}x-4=\frac{19}{20}\\x-4=-\frac{19}{20}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{19}{20}+4=\frac{99}{20}\\x=-\frac{19}{20}+4=\frac{61}{20}\end{matrix}\right.\)
7) \(\left|x-\frac{5}{4}\right|=-\frac{1}{3}\)
Vì \(\left|x-\frac{5}{4}\right|\ge0\)
=> Không có giá trị x thỏa mãn với điều kiện trên
a) \(\left|\frac{4}{7}-x\right|+\frac{2}{5}=0\)
=> \(\left|\frac{4}{7}-x\right|=-\frac{2}{5}\), vô lí vì \(\left|\frac{4}{7}-x\right|\ge0\)
Vậy không tồn tại giá trị của x thỏa mãn đề bài
b) \(6-\left|\frac{1}{4}x+\frac{2}{5}\right|=0\)
=> \(\left|\frac{1}{4}x+\frac{2}{5}\right|=6-0=6\)
=> \(\left[\begin{array}{nghiempt}\frac{1}{4}x+\frac{2}{5}=6\\\frac{1}{4}x+\frac{2}{5}=-6\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}\frac{1}{4}x=\frac{28}{5}\\\frac{1}{4}x=-\frac{32}{5}\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=\frac{112}{5}\\x=-\frac{128}{5}\end{array}\right.\)
Vậy \(\left[\begin{array}{nghiempt}x=\frac{112}{5}\\x=-\frac{128}{5}\end{array}\right.\)
c) \(\left|x-\frac{1}{3}\right|+\left|2-\frac{4}{5}\right|=0\)
=> \(\left|x-\frac{1}{3}\right|+\left|\frac{6}{5}\right|=0\)
=> \(\left|x-\frac{1}{3}\right|+\frac{6}{5}=0\)
=> \(\left|x-\frac{1}{3}\right|=-\frac{6}{5}\), vô lí vì \(\left|x-\frac{1}{3}\right|\ge0\)
Vậy không tồn tại giá trị của x thỏa mãn đề bài
\(\left|x+5\right|=5\)
<=> \(\hept{\begin{cases}x+5=5\\x+5=-5\end{cases}}\)
<=> \(\hept{\begin{cases}x=0\\x=-10\end{cases}}\)
\(\left|x+1\right|+7=10\)
<=> \(\left|x+1\right|=3\)
<=> \(\hept{\begin{cases}x+1=3\\x+1=-3\end{cases}}\)
<=> \(\hept{\begin{cases}x=2\\x=-4\end{cases}}\)
\(\left|x-3\right|-6=5\)
<=> \(\left|x-3\right|=11\)
<=> \(\hept{\begin{cases}x-3=11\\x-3=-11\end{cases}}\)
<=> \(\hept{\begin{cases}x=14\\x=-8\end{cases}}\)
\(\left|x+2\right|-6\left(x-4\right)=20-6x\)
<=> \(\left|x+2\right|-6x+24=20-6x\)
<=> \(\left|x+2\right|=-4\)
<=> \(\hept{\begin{cases}x+2=-4\\x+2=4\end{cases}}\)
<=> \(\hept{\begin{cases}x=-2\\x=2\end{cases}}\)
a) \(|x+5|=5\)
\(\Rightarrow\orbr{\begin{cases}x+5=5\\x+5=-5\end{cases}}\Rightarrow\orbr{\begin{cases}x=0\\x=-10\end{cases}}\)
Vậy x = 0 hoặc x = -10
b) \(|x+1|+7=10\)
\(\Rightarrow|x+1|=10-7\)
\(\Rightarrow|x+1|=3\)
\(\Rightarrow\orbr{\begin{cases}x+1=3\\x+1=-3\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=-4\end{cases}}\)
Vậy x = 2 hoặc x = -4
c) \(|x-3|-6=5\)
\(\Rightarrow|x-3|=5+6\)
\(\Rightarrow|x-3|=11\)
\(\Rightarrow\orbr{\begin{cases}x-3=11\\x-3=-11\end{cases}}\Rightarrow\orbr{\begin{cases}x=14\\x=-8\end{cases}}\)
Vậy x = 14 hoặc x = -8
d) \(|x+2|-6\left(x-4\right)=20-6x\)
\(\Rightarrow|x+2|-6x+24=20-6x\)
\(\Rightarrow|x+2|=20-6x-24+6x\)
\(\Rightarrow|x+2|=\left(20-24\right)+\left(-6x+6x\right)\)
\(\Rightarrow|x+2|=-4\)
Vì \(|x|\ge0\)mà \(|x+2|=-4\)
\(\Rightarrow\)Không có giá trị x thỏa mãn
_Chúc bạn học tốt_
\(\left(2x+1\right)^3=125\)
\(\left(2x+1\right)^3=5^3\)
\(2x+1=5\)
\(2x=4\)
\(x=2\)
\(b,x^6=x^2\)
\(x^6-x^2=0\)
\(x^2\cdot\left(x^4-1\right)=0\)
\(\orbr{\begin{cases}x^2=0\\x^4-1=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)
\(c\text{}\text{}\text{}\text{},\left(x-2\right)\cdot\left(x-5\right)=0\)
\(\orbr{\begin{cases}x-2=0\\x-5=0\end{cases}\Rightarrow\orbr{\begin{cases}x=2\\x=5\end{cases}}}\)
\(d,x^{10}-x^5=0\)
\(x^5\cdot\left(x^5-1\right)=0\)
\(\orbr{\begin{cases}x^5=0\\x^5=1\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}}\)
\(e,\left(x-5\right)^4=\left(x-5\right)^6\)
\(\left(x-5\right)^4-\left(x-5\right)^6=0\)
\(\left(x-5\right)^4\cdot\left[1-\left(x-5\right)^2\right]=0\)
\(\orbr{\begin{cases}\left(x-5\right)^4=0\\1-\left(x-5\right)^2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=5\\x=\pm1+5\end{cases}}}\)
\(\hept{\begin{cases}x=5\\x=6\\x=4\end{cases}}\)
\(\left(2x+1\right)^3=125\Rightarrow\left(2x+1\right)^3==5^3\Rightarrow2x+1=5\)
\(\Rightarrow2x=5-1=4\Rightarrow x=4:2=2\)
\(x^6=x^2\Rightarrow x^2.x^4=x^2\)Vì vậy nên \(x=\pm1\)
\(\left(x-2\right)\left(x-5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\Rightarrow x=0+2=5\\x-5=0\Rightarrow X=0+5=5\end{cases}}\)
a: \(\Leftrightarrow2^x=1024\cdot3+1024\cdot7776+7776\cdot5\)
\(\Leftrightarrow2^x=8004576\)
hay \(x\in\varnothing\)
b: \(\Leftrightarrow x\left(x+3\right)^{100}-\left(x+3\right)^{100}=0\)
\(\Leftrightarrow\left(x+3\right)^{100}\left(x-1\right)=0\)
=>x=-3 hoặc x=1