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\(\left(x-3\right)\left(x-12\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x-12=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=12\end{cases}}\)
\(\Rightarrow x\in\left\{3;12\right\}\)
\(\left(x^2-81\right)\left(x^2+9\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x^2-81=0\\x^2+9=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=9\\x\in\varnothing\end{cases}}\Leftrightarrow x=9\)
\(\Rightarrow x=9\)
\(\left(x-4\right)\left(x+2\right)< 0\)
\(\Rightarrow\hept{\begin{cases}x-4\\x+2\end{cases}}\)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 \(x\in\left\{-1;0;1;2;3\right\}\)
a) 4x + 32 = 3 . 25
4x + 32 = 3 . 32 = 96
4x = 96 - 32 = 64
4x = 43
=> x = 3
b) 86 - 5( x + 8 ) = 616 : 614 ( Bài này mình bấm máy k ra :v Xem lại nhé )
c) 38 - 3 | x | = 5 ( 24 - 22 . 3 )
38 - 3 | x | = 5 ( 16 - 4 . 3 )
38 - 3 | x | = 5 . 4
38 - 3 | x | = 20
3 | x | = 38 - 20
3 | x | = 18
| x | = 18 : 3 = 6
=> x = 6 hoặc x = -6
d) 2018 < | x | < 2020
=> | x | = { 2019 ; 2020 }
=> x = { -2019 ; 2019 ; -2020 ; 2020 }
a) \(2^x.4=128\)
\(2^x=128:4\)
\(2^x=32\)
\(2^x=2^5\)
\(\Rightarrow x=5\)
vay \(x=5\)
b) \(\left(2x+1\right)^3=125\)
\(\left(2x+1\right)^3=5^3\)
\(\Rightarrow2x+1=5\)
\(\Rightarrow2x=4\)
\(\Rightarrow x=2\)
vay \(x=2\)
Ta có : 2x + 2x + 1 = 24
=> 2x(1 + 2) = 24
=> 2x.3 = 24
=> 2x = 8
=> 2x = 23
=> x = 3
Ta có : (x + 2)4 = (x + 2)6
=> (x + 2)4 - (x + 2)6 = 0
<=> (x + 2)4 (1 - (x + 2)2) = 0
<=> \(\orbr{\begin{cases}\left(x+2\right)^4=0\\\left(1-\left(x+2\right)^2\right)=0\end{cases}}\)
<=> \(\orbr{\begin{cases}x+2=0\\\left(x+2\right)^2=1\end{cases}}\)
<=> \(\orbr{\begin{cases}x+2=0\\x+2=1\end{cases}}\)
<=> \(\orbr{\begin{cases}x=-2\\x=-1\end{cases}}\)
Ta có :
\(S=2+2^2+.....+2^{100}\)
\(\Rightarrow2S=2^2+2^3+....+2^{101}\)
\(\Rightarrow2S-S=\left(2^2+2^3+.....+2^{101}\right)-\left(2+2^2+....+2^{100}\right)\)
\(\Rightarrow S=2^{101}-2\)
| x + 3 | + 3x = 15
=> |x+3|=15-3x
TH1 : x+3=-(15-3x)
=> x+3 = -15+3x
=> x= -15+3x-3
=> x= (-15-3 )+3x
=> x = -18+3x
=> 0= -18+(3x-x)
=> 0=-18+2x
=> 2x = 18
=> x = 9
a)83-6.(x-7)=35
6(x-7)=83-35=48
x-7=48:6=8
x=8+7=15
b)246+7.(x+15)=442
7(x+15)=442-246=196
x+15=196:7=28
x=28-15=13
a, 2.(x+15)=40
2x+30=40
2x = 10
x = 5
Vậy x=5
b, 9.x-33=\(3^{2015}:3^{2014}\)
9.x-33=3
9.x =36
x = 4
Vậy x= 4