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\(\frac{12}{16}=-\frac{x}{4}=\frac{21}{y}=\frac{z}{-80}\)
Ta có : \(\frac{12}{16}=-\frac{x}{4}\Rightarrow16.-x=12.4\Rightarrow16.-x=48\)
\(\Rightarrow-x=3\Rightarrow x=-3\)
\(\frac{12}{16}=\frac{21}{y}\Rightarrow12.y=16.21\Rightarrow12.y=336\)
\(\Rightarrow y=28\)
\(\frac{12}{16}=\frac{z}{-80}\Rightarrow16.z=12.-80\Rightarrow16.z=-960\)
\(\Rightarrow z=60\)
Vậy x = - 3 ; y = 28 ; z = 60
Ta có:
\(\frac{12}{16}=\frac{-x}{4}=\frac{21}{y}=\frac{z}{-80}\)
\(\Leftrightarrow\frac{12}{16}=\frac{-x}{4}=\frac{21}{y}=\frac{-z}{80}\) (Chuyển mẫu âm thành dương)
\(\frac{-x}{4}=\frac{12}{16}=\frac{12:\left(-4\right)}{16:\left(-6\right)}=\frac{-3}{-4}=\frac{3}{4}\Rightarrow x=-3\) (Ta chuyển mẫu âm thành dương)
\(\frac{21}{y}=\frac{3}{4}=\frac{3.7}{4.7}=\frac{21}{28}\Rightarrow y=28\)
\(\frac{-z}{80}=\frac{21}{28}\) ( Vì 80 : 28 không hết) \(\Rightarrow z=\varnothing\)
\(\Rightarrow\hept{\begin{cases}-3\\28\\\varnothing\end{cases}}\)
\(l,\\ 2^x=1=2^0\\ Vậy:x=0\\ m,\\ 3^x=81=3^4\\ Vậy:x=4\\ n,\\ 3^x=37=3^3\\ Vậy:x=3\\ o,\\ 9^x=3^4=\left(3^2\right)^2=9^2\\ Vậy:x=2\)
Ta có: \(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+2013\right)=4+1007\cdot2013\)
\(\Leftrightarrow2014x+2027091=2027095\)
\(\Leftrightarrow2014x=4\)
hay \(x=\dfrac{2}{1007}\)
`@` `\text {Ans}`
`\downarrow`
`2+(x+3)=7`
`\Rightarrow x+3=7-2`
`\Rightarrow x+3=5`
`\Rightarrow x=5-3`
`\Rightarrow x=2`
`5+(3+x)=10`
`\Rightarrow 3+x=10-5`
`\Rightarrow 3+x=5`
`\Rightarrow x=5-3`
`\Rightarrow x=2`
`(4+x)+1=7`
`\Rightarrow 4+x=7-1`
`\Rightarrow 4+x=6`
`\Rightarrow x=6-4`
`\Rightarrow x=2`
`(x+5)+3=9`
`\Rightarrow x+5=9-3`
`\Rightarrow x+5=6`
`\Rightarrow x=6-5`
`\Rightarrow x=1`
`(x-1)-4=7`
`\Rightarrow x-1=7+4`
`\Rightarrow x-1=11`
`\Rightarrow x=11+1`
`\Rightarrow x=12`
`4-(6-x)=1`
`\Rightarrow 6-x=4-1`
`\Rightarrow 6-x=3`
`\Rightarrow x=6-3`
`\Rightarrow x=3`
\(2+\left(x+3\right)=7\)
\(\Rightarrow2+x+3=7\)
\(\Rightarrow x+5=7\)
\(\Rightarrow x=2\)
\(5+\left(3+x\right)=10\)
\(\Rightarrow5+3+x=10\)
\(\Rightarrow x+8=10\)
\(\Rightarrow x=2\)
\(\left(4+x\right)+1=7\)
\(\Rightarrow4+x+1=7\)
\(\Rightarrow x+5=7\)
\(\Rightarrow x=2\)
\(\left(x+5\right)+3=9\)
\(=x+5+3=9\)
\(\Rightarrow x+8=9\)
\(\Rightarrow x=1\)
\(\left(x-1\right)-4=7\)
\(\Rightarrow x-1-4=7\)
\(\Rightarrow x-5=7\)
\(\Rightarrow x=12\)
\(4-\left(6-x\right)=1\)
\(\Rightarrow4-6-x=1\)
\(\Rightarrow-2-x=1\)
\(\Rightarrow x=-3\)
\(|-x+1|=4\)có 2 trường hợp.
th1: -x+1=4
-x=4-1=3
=> x=-3
th2:-x+1=-4
-x=-4-1=-5
=>x=5
vậy x=-3 hoặc x=5
hihi^^
\(3\cdot\left(x-4\right)=4x-80\)
\(3x-12=4x+80\)
\(3x-12-4x+80=0\)
\(-x+68=0\)
\(-x=-68\)
\(x=68\)
4x + 4x+1 = 80
4x . ( 1+4)= 80
4x . 5 = 80
4x = 80:5
4x = 16
4x = 42
=> x = 2
Vậy x=2
\(4^x+4^{x+1}=80\)
\(4^x.\left(1+4\right)=80\)
\(4^x.5=80\)
\(4^x=\frac{80}{5}\)
\(4^x=16\)
\(4^x=4^2\)
\(\Rightarrow x=2\)
Vậy \(x=2\)