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\(5^x+5^{x+2}+5^{x+4}=3255\)
\(\Rightarrow5^x\left(1+5^2+5^4\right)=3255\)
\(\Rightarrow5^x.651=3255\)
\(\Rightarrow5^x=5\Rightarrow x=1\)
1: =>25x-15-6x+12=11-5x
=>19x-3=11-5x
=>24x=14
=>x=7/12
2: =>8-12x-5+10x=4-6x
=>4-6x=-2x+3
=>-4x=-1
=>x=1/4
\(|x^2-5x+4|=4x-4\)
\(\Rightarrow|\left(x-1\right)\left(x-4\right)|=4\left(x-1\right)\)
\(\Rightarrow\orbr{\begin{cases}\left(x-1\right)\left(x-4\right)=4\left(x-1\right)\\\left(x-1\right)\left(x-4\right)=-4\left(x-1\right)\end{cases}}\)
TH1 :
\(\left(x-1\right)\left(x-4\right)=4\left(x-1\right)\)
\(\Rightarrow\left(x-1\right)\left(x-4\right)-4\left(x-1\right)=0\)
\(\Rightarrow\left(x-1\right)\left(x-8\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x=8\end{cases}}\)
Th2:
\(\left(x-1\right)\left(x-4\right)=-4\left(x-1\right)\)
\(\Rightarrow\left(x-1\right)\left(x-4\right)+4\left(x-1\right)=0\)
\(\Rightarrow\left(x-1\right)x=0\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x=0\end{cases}}\)
\(\Rightarrow S=\left\{0;1;8\right\}\)
\(\frac{4+5x}{-2}=\frac{4}{\left(5x+4\right)^2}\)
\(\frac{5x+4}{-2}=\frac{4}{\left(5x+4\right)^2}\)
\(\Leftrightarrow\left(5x+4\right)^2\cdot\left(5x+4\right)=4\cdot\left(-2\right)\)
\(\Leftrightarrow\left(5x+4\right)^3=-8=\left(-2\right)^3\)
\(\Leftrightarrow5x+4=-2\)
\(\Leftrightarrow5x=-6\)
\(\Leftrightarrow x=\frac{-6}{5}\)
`@` `\text {Ans}`
`\downarrow`
`1)`
\(2x+\dfrac{1}{2}=\dfrac{5}{3}\)
`\Rightarrow`\(2x=\dfrac{5}{3}-\dfrac{1}{2}\)
`\Rightarrow`\(2x=\dfrac{7}{6}\)
`\Rightarrow`\(x=\dfrac{7}{6}\div2\)
`\Rightarrow`\(x=\dfrac{7}{12}\)
Vậy, `x = 7/12`
`2)`
\(\dfrac{1}{7}+\dfrac{4}{5}x=\dfrac{5}{3}\)
`\Rightarrow`\(\dfrac{4}{5}x=\dfrac{5}{3}-\dfrac{1}{7}\)
`\Rightarrow`\(\dfrac{4}{5}x=\dfrac{32}{21}\)
`\Rightarrow`\(x=\dfrac{32}{21}\div\dfrac{4}{5}\)
`\Rightarrow`\(x=\dfrac{40}{21}\)
Vậy, `x = 40/21`
`3)`
\(\dfrac{3}{5}-\dfrac{3}{5}x=\dfrac{1}{7}\)
`\Rightarrow`\(\dfrac{3}{5}x=\dfrac{3}{5}-\dfrac{1}{7}\)
`\Rightarrow`\(\dfrac{3}{5}x=\dfrac{16}{35}\)
`\Rightarrow`\(x=\dfrac{16}{35}\div\dfrac{3}{5}\)
`\Rightarrow`\(x=\dfrac{16}{21}\)
Vậy, `x = 16/21`
`4)`
\(\dfrac{5}{6}-3x=\dfrac{3}{4}\)
`\Rightarrow`\(3x=\dfrac{5}{6}-\dfrac{3}{4}\)
`\Rightarrow`\(3x=\dfrac{1}{12}\)
`\Rightarrow`\(x=\dfrac{1}{12}\div3\)
`\Rightarrow`\(x=\dfrac{1}{36}\)
Vậy, `x = 1/36`
`5)`
\(\dfrac{5}{3}-\dfrac{1}{2}x=\dfrac{3}{7}\)
`\Rightarrow`\(\dfrac{1}{2}x=\dfrac{5}{3}-\dfrac{3}{7}\)
`\Rightarrow`\(\dfrac{1}{2}x=\dfrac{26}{21}\)
`\Rightarrow`\(x=\dfrac{26}{21}\div\dfrac{1}{2}\)
`\Rightarrow`\(x=\dfrac{52}{21}\)
Vậy, `x = 52/21`
`6)`
\(5x+\dfrac{1}{2}=\dfrac{2}{3}\)
`\Rightarrow`\(5x=\dfrac{2}{3}-\dfrac{1}{2}\)
`\Rightarrow`\(5x=\dfrac{1}{6}\)
`\Rightarrow`\(x=\dfrac{1}{6}\div5\)
`\Rightarrow`\(x=\dfrac{1}{30}\)
Vậy, `x = 1/30.`
Lời giải:
1. $(x+2)-2=0$
$x+2=2$
$x=0$
2.
$(x+3)+1=7$
$x+3=7-1=6$
$x=6-3=3$
3.
$(3x-4)+4=12$
$3x-4+4=12$
$3x=12$
$x=12:3=4$
4.
$(5x+4)-1=13$
$5x+4=13+1=14$
$5x=14-4=10$
$x=10:5=2$
5.
$(4x-8)-3=5$
$4x-8=5+3=8$
$4x=8+8=16$
$x=16:4=4$
6.
$3+(x-5)=7$
$x-5=7-3=4$
$x=4+5=9$
7.
$8-(2x-4)=2$
$2x-4=8-2=6$
$2x=6+4=10$
$x=10:2=5$
8.
$7+(5x+2)=14$
$5x+2=14-7=7$
$5x=7-2=5$
$x=5:5=1$
9.
$5-(3x-11)=1$
$3x-11=5-1=4$
$3x=11+4=15$
$x=15:3=5$
10.
$16-(8x+2)=6$
$8x+2=16-6=10$
$8x=10-2=8$
$x=8:8=1$
a)\(|4+5x|+5x=-4\)
\(|4+5x|=-4-5x\)
\(\Rightarrow\left[{}\begin{matrix}4+5x=-4-5x\\4+5x=-\left(-4-5x\right)\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}5x+5x=-4-4\\4+5x=4+5x\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}10x=-8\\5x-5x=4-4\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{8}{10}\Rightarrow x=\frac{4}{5}\\\\0=0\left(loai\right)\end{matrix}\right.\)
Vậy \(x=\frac{4}{5}\)
2: 12-10x=25-30x
=>20x=13
=>x=13/20
3: \(3\left(2x+3\right)-2\left(4x-5\right)=10x+21\)
=>6x+9-8x+10=10x+21
=>10x+21=-2x+19
=>12x=-2
=>x=-1/6
4: \(\Leftrightarrow25x-15-6x+12=11-5x\)
=>19x-3=11-5x
=>24x=14
=>x=7/12
5: \(\Leftrightarrow8-12x-5+10x=4-6x\)
=>4-6x=-2x+3
=>-4x=-1
=>x=1/4
6: \(\Leftrightarrow32x-24-6+9x=13-40x\)
=>41x-30=13-40x
=>81x=43
=>x=43/81
7: \(\Leftrightarrow10x-5+20x=5x-11\)
=>30x-5=5x-11
=>25x=-6
=>x=-6/25