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\(A=2^0+2^1+2^2+2^3+...+2^{2009}\)
\(=>2A=2^1+2^2+2^3+...+2^{2009}+2^{2010}\)
\(=>2A-A=\left(2^1+2^2+2^3+...+2^{2009}+2^{2010}\right)-\left(2^0+2^1+2^2+2^3+...+2^{2009}\right)\)
\(\left(\dfrac{1}{64}-\dfrac{1}{3^2}\right)\left(\dfrac{1}{64}-\dfrac{1}{4^2}\right)...\left(\dfrac{1}{64}-\dfrac{1}{64^2}\right)\)
\(=\left(\dfrac{1}{64}-\dfrac{1}{3^2}\right)\left(\dfrac{1}{64}-\dfrac{1}{4^2}\right)...\left(\dfrac{1}{64}-\dfrac{1}{8^2}\right)...\left(\dfrac{1}{64}-\dfrac{1}{64^2}\right)\)
\(=\left(\dfrac{1}{64}-\dfrac{1}{3^2}\right)\left(\dfrac{1}{64}-\dfrac{1}{4^2}\right)...0...\left(\dfrac{1}{64}-\dfrac{1}{64^2}\right)\)
\(=0\)
Vậy...
`@` `\text {Ans}`
`\downarrow`
\(\left(2\cdot x+2\right)^2=64\)
`\Rightarrow`\(\left(2x+2\right)^2=\left(\pm8\right)^2\)
`\Rightarrow`\(\left[{}\begin{matrix}2x+2=8\\2x+2=-8\end{matrix}\right.\)
`\Rightarrow`\(\left[{}\begin{matrix}2x=8+2\\2x=-8+2\end{matrix}\right.\)
`\Rightarrow`\(\left[{}\begin{matrix}2x=10\\2x=-6\end{matrix}\right.\)
`\Rightarrow`\(\left[{}\begin{matrix}x=10\div2\\x=-6\div2\end{matrix}\right.\)
`\Rightarrow`\(\left[{}\begin{matrix}x=5\\x=-3\end{matrix}\right.\)
Vậy, `x \in {5; -3}`
`@` `\text {Kaizuu lv uuu}`
Bài làm
196:{64-196:{64-[18+2.(25-21)2]}}
=196:{64-196:{64-[18+2.42]}}
=196:{64-196:{64-[18+2.16]}}
=196:{64-196:{64-[18+32]}}
=196:{64-196:{64-50}}
=196:{64-196:14}
=196:{64-14}
=196:50
=3,92
# Chúc bạn học tốt #
196 : { 64 - 196 : { 64 - [ 18 + 2 . ( 25 - 21 )2 ] }
= 196 : { 64 - 196 : { 64 - [ 18 + 2 . 42 ] }
= 196 : { 64 - 196 : { 64 - [ 18 + 2 . 16 ] }
= 196 : { 64 - 196 : { 64 - [ 18 + 32 ] }
= 196 : { 64 - 196 : { 64 - 50 } }
= 196 : { 64 - 196 : 14 }
= 196 : { 64 - 14 }
= 196 : 50
= 3, 92
thoạt tiên bn đã vt sai đề :(chỗ in đậm)
196:{64-196:{64-[18+2(25-21)2]}}
=196:{64-196:{64-[18+2.42]}}
=196:{64-196:{64-[18+32]}}
=196:{64-196:{64-50}}
=196:{64-196:14}}
=196:{64-14}
=196:50
=3.92
a) \(123+\left[54+\left(-123\right)+46\right]\)
\(=123+54+\left(-123\right)+46\)
\(=54+46\)
\(=100\)
b) \(-64+\left[\left(-111\right)+64+71\right]\)
\(=-64+\left(-111\right)+64+71\)
\(=\left(-111\right)+71\)
\(=-40\)
c) 64.7 + 36.7 = 7.(64 + 36) = 7.100 = 700
d) 3.52 - 64 : 23 = 3.25 - 64 : 8 = 75 - 8 = 67
a) ( 5x - 2 )2 = 64
( 5x - 2 )2 = 82
\(\Rightarrow\)5x - 2 = 8
5x = 10
x = 2
b) 25x+1 = 64
25x + 1 = 26
\(\Rightarrow\)5x + 1 = 6
5x = 5
x = 1
Hk tốt
a) ( 5x - 2 )2 = 64
( 5x - 2)2 = 82
5x - 2 = 8
5x = 10
x = 10 : 5 = 2
b) 25x + 1 = 64
25x+1 = 26
5x + 1 = 6
5x = 5
x = 5 : 5 = 1
a)16. x2 = 64
x2 = 64 : 16
x2 = 4
x2 = 22
⇒ x = 2
b) (5.x - 2) - 64 = -36
(5.x - 2) = -36 + 64
5.x - 2 = 28
5.x = 28 + 2
5.x = 30
x = 30 : 5
x = 6
c) (2x - 10).(5 - x) = 0
TH1: 2x - 10 = 0
2x = 0 + 10
2x = 10
x = 10 : 2
x = 5
TH2: 5 - x = 0
x = 5 - 0
x = 5
⇒ Vậy x = 5.
\(6\cdot6\cdot6\cdot6\cdot3\cdot2\)
\(=6\cdot6\cdot6\cdot6\cdot\left(3\cdot2\right)\)
\(=6\cdot6\cdot6\cdot6\cdot6\)
\(=6^5\)
⇒ Chọn D
\(2^5\cdot64=2^5\cdot2^6=2^{11}=2048\)
\(20\cdot5\cdot10^3=100\cdot1000=100000\)
32.64
=2048
100.103
=100.1000
=100000