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\(C=1+\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{18}}=1+1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{8}+...+\dfrac{1}{131072}-\dfrac{1}{262144}=1+1-\dfrac{1}{262144}=2-\dfrac{1}{262144}\)
\(a)3-\left(17-x\right)=-24+12\)
\(\Leftrightarrow3-17+x=-12\)
\(\Leftrightarrow-14+x=-12\)
\(\Leftrightarrow x=-12+14=2\)
a) 3 - (17 - x) = -24 + 12
=> 3 - 17 + x = -12
=> -14 + x = -12
=> x = -12 + 14
=> x = 2
b) -5 + (16 - x) = 22.3 - 52
=> -5 + 16 - x = 12 - 25
=> 11 - x = -13
=> x = 11 + 13
=> x = 24
c) -26 - (x - 7) = 34 - 92
=> -26 - x + 7 = 81 - 81
=> -19 - x = 0
=> x = -19 - 0
=> x = -19
d) -36 - (4 - x) = 37 + (-5)
=> -36 - 4 + x = 32
=> -40 + x = 32
=> x = 32 + 40
=> x = 72
\(a/\) \(\left(-77\right)+27=\left(-50\right)\)
\(b/\left(-146\right)+\left(-54\right)=\left(-200\right)\)
\(c/-\left(19-82\right)+\left(98-82\right)\)
\(=-\left(-63\right)+16\)
\(=\left(-47\right)\)
\(d/\left|-6\right|+\left(-7\right)+\left|-4\right|+\left(-3\right)\)
\(=6+\left(-7\right)+4+\left(-3\right)\)
\(=6+4-7-3=0\)
\(e/\left(-17\right)+5+8+17+\left(-3\right)\)
\(=\left(-17\right)+17+13-3\)
\(=0+10=10\)
\(f/25\cdot2^2-\left(15-18\right)+\left(12-19+10\right)\)
\(=25\cdot4-\left(-3\right)+3\)
\(=100+3+3=106\)
\(g/15^2-\left(15+9\right):2^2+3\cdot\left(4^2\right)+1\)
\(=225-24:4+3\cdot\left(16+1\right)\)
\(=225-6+3\cdot17\)
\(=219+51\)
\(=270\)
(...chắc sai...> . < ...)
1)x=-30
2)x=-81
3)x=4
4)x=62
5)x=6
6)-13
7)-13
8)-31
9)x=-6;0;6;12
tk minh nha
1. 3x - 9 = (-1) - x
=> 3x + x = (-1) + 9
=> 4x = 8
=> x = 8 : 4
=> x = 2
2. 2x - 23 = 17 - 3x
=> 2x - 8 = 17 - 3x
=> 2x + 3x = 17 + 8
=> 5x = 25
=> x = 25 : 5
=> x = 5
3. |x - 3| + 8 = 12
=> |x - 3| = 12 - 8
=> |x - 3| = 4
=> \(\orbr{\begin{cases}x-3=4\\x-3=-4\end{cases}}\)
=> \(\orbr{\begin{cases}x=4+3\\x=-4+3\end{cases}}\)
=> \(\orbr{\begin{cases}x=7\\x=-1\end{cases}}\)
4. 12 - 2|x| = |-2012|
=> 12 - 2|x| = 2012
=> 2|x| = 12 - 2012
=> 2|x| = -2000
=> |x| = -2000 : 2
=> |x| = -1000
=> x không có số nào thỏa mãn
5. 19 - (14 + 19) = x - (27 - 9)
=> 19 - 14 - 19 = x - 18
=> -14 = x - 18
=> x - 18 = -14
=> x = -14 + 18
=> x = 4
6. 15 - |x - 3| = 2
=> |x - 3| = 15 - 2
=> |x - 3| = 13
=> \(\orbr{\begin{cases}x-3=13\\x-3=-13\end{cases}}\)
=> \(\orbr{\begin{cases}x=13+3\\x=-13+3\end{cases}}\)
=> \(\orbr{\begin{cases}x=16\\x=10\end{cases}}\)
7. |x - 5| - 27 = -6
=> |x - 5| = -6 + 27
=> |x - 5| = 21
=> \(\orbr{\begin{cases}x-5=21\\x-5=-21\end{cases}}\)
=> \(\orbr{\begin{cases}x=21+5\\x=-21+5\end{cases}}\)
=> \(\orbr{\begin{cases}x=26\\x=-16\end{cases}}\)
8. 3 . |x - 2| = |-15|
=> 3 . |x - 2| = 15
=> |x - 2| = 15 : 3
=> |x - 2| = 5
=> \(\orbr{\begin{cases}x-2=5\\x-2=-5\end{cases}}\)
=> \(\orbr{\begin{cases}x=5+2\\x=-5+2\end{cases}}\)
=> \(\orbr{\begin{cases}x=7\\x=-3\end{cases}}\)
9. 11 - 2|x| = -3
=> 2|x| = 11 - (-3)
=> 2|x| = 14
=> |x| = 14 : 2
=> |x| = 7
=> \(\orbr{\begin{cases}x=7\\x=-7\end{cases}}\)
10.|x - 2| = 1
=> \(\orbr{\begin{cases}x-2=1\\x-2=-1\end{cases}}\)
=> \(\orbr{\begin{cases}x=1+2\\x=-1+2\end{cases}}\)
=> \(\orbr{\begin{cases}x=3\\x=1\end{cases}}\)