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a) \(3^x-27.3^5.3^2=0\)
\(3^x-3^3.3^5.3^3=0\)
\(3^x=3^{13}\)
\(x=13\)
b) \(\left(-5+3x\right):4=16\)
\(-5+3x=64\)
\(3x=69\)
\(x=23\)
\(\dfrac{2\text{x}-1}{3}=\dfrac{3\text{x}+1}{4}\)
\(\Leftrightarrow=\dfrac{4\left(2\text{x}-1\right)}{12}=\dfrac{3\left(3\text{x}+1\right)}{12}\)
\(\Leftrightarrow8\text{x}-4=9\text{x}+3\)
\(\Leftrightarrow8\text{x}-9\text{x}=3+4\)
\(\Leftrightarrow-x=7\)
\(\Leftrightarrow x=-7\)
| 2x-1 | -1 | -35 | 1 | 35 | 5 | -5 |
| 2y+1 | 35 | 1 | -35 | -1 | -7 | 7 |
| x | 0 | -17 | 1 | 18 | 3 | -2 |
| y | -1 | 0 | -18 | -1 | -4 | 3 |
| 2x-1 | 7 | -7 | ||||
| 2y+1 | -5 | 5 | ||||
| x | 4 | -3 | ||||
| y | -3 | 2 |
a/2.x-35=15
2.x =15+35
2.x =50
x =50:2=25
b/3.x+17=2
3.x =2-17
3.x =-15
x =-15:3=-5
c/|x-1|=0
=>x=1
Mà lớp bạn giờ mới học tới bài này thôi hả,chậm thế
a 2x-35=15
2x = 15+35
2x = 40
x = 20
b 3x+17 =2
3x = 2-17
3x = -15
x = -15:3
x = -5
c |x-1| = 0
=> x-1 = 0
x = 0+1
x = 1
khong biet co dung khong neu dung thi tick nhe
a, -16 + 23 + x = -16
=> -7 + x = -16
=> x = -16 - (-7)
=> x = -9
b, 2x - 35 = 15
=> 2x = 15 + 35
=> 2x = 50
=> x = 50 : 2
=> x = 25
c, 3x + 17 =11
=> 3x = 11 - 17
=> 3x = -6
=> x = -6 : 3
=> x = -2
d, | x - 1 | = 0
=> x - 1 = 0
x = 0 + 1
x = 1
e, -13 . | x | = -26
=> | x | = -26 : (-13)
=> | x | = 2
=> x = 2
\(\left(x-3\right)\left(x-12\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x-12=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=12\end{cases}}\)
\(\Rightarrow x\in\left\{3;12\right\}\)
\(\left(x^2-81\right)\left(x^2+9\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x^2-81=0\\x^2+9=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=9\\x\in\varnothing\end{cases}}\Leftrightarrow x=9\)
\(\Rightarrow x=9\)
\(\left(x-4\right)\left(x+2\right)< 0\)
\(\Rightarrow\hept{\begin{cases}x-4\\x+2\end{cases}}\)trái dấu
\(TH1:\hept{\begin{cases}x-4>0\\x+2< 0\end{cases}}\Leftrightarrow\hept{\begin{cases}x>4\\x< -2\end{cases}}\Leftrightarrow x\in\varnothing\)
\(TH2:\hept{\begin{cases}x-4< 0\\x+2>0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x< 4\\x>-2\end{cases}}\Leftrightarrow x\in\left\{-1;0;1;2;3\right\}\)
Vậy \(x\in\left\{-1;0;1;2;3\right\}\)
Bài 1:
a) 15-x=7-(-2)
15-x=9
x=15-9
x=6
b) x-35=(-12)-3
x-35=-15
x=-15+35
x=20
c) \(\left|x+2\right|=0\)
=> x+2=0
=> x=0-2
x=-2
d) \(\left|x-5\right|=7\)
\(\orbr{\begin{cases}x-5=7\\x-5=-7\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=12\\x=-2\end{cases}}\)
Bài 2
a) Tổng ba số là:
15+(-30)+x=-15+x
b) -15+x=45
x=45-(-15)
x=60
c)-15+x=-45
x=-45-(-15)
x=-30
cho mình nhé
Theo đề, ta có: \(\dfrac{1+2x}{18}=\dfrac{1+4x}{34}\)
\(\Leftrightarrow34\left(1+2x\right)=18\left(1+4x\right)\)
\(\Leftrightarrow34+68x=18+72x\)
\(\Leftrightarrow34-18=72x-68x\)
\(\Leftrightarrow16=4x\)
\(\Leftrightarrow x=4\)
Khi \(x=4\) vào ta có: \(\dfrac{1+4.4}{34}=\dfrac{1+6.4}{2y^2}\Leftrightarrow\dfrac{1}{2}=\dfrac{25}{2y^2}\)
\(\Leftrightarrow2y^2=50\)
\(\Leftrightarrow y^2=50\)
\(\Leftrightarrow y=\pm5\)
a)2x-35=15
2x=15+35
2x=50
x=50:2
x=25
b)3x+17=2
3x=2-17
3x=-15
x=-15:3
x=-5
c)|x-1|=0
=>x-1=0=>x=0-1
=>x=-1
a)2x-35=15
2x=15+35
2x=50
x=50:2
x=25
b)3x+17=2
3x=2-17
3x=-15
x=-15:3
x=-5
c)|x-1|=0
x-1=0
x=0+1
x=1