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a) \(25.8^3-23.8^3=8^3\left(25-23\right)\)
\(=8^3.2\)
\(=2^9.2=2^{10}\)
b) \(5^4-2.5^3=5^3.5-2.5^3\)
\(=5^3\left(5-2\right)\)
\(=5^3.3=375\)
c)\(2.4^3-4^3.7-6.4^3=4^3\left(2-7-6\right)\)
\(=4^3.-11=-704\)
d)\(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right].10^3\)
\(=3^2.10^3-\left[13^2-2^2\left(5^2+15\right)\right].10^3\)
\(=3^2.10^3-\left[13^2-2^2.40\right].10^3\)
\(=10^3\left[3^2-9\right]\)
\(=0\)
Bài 1 :
a) \(25.8^3-23.8^3\)
\(=8^3.\left(25-23\right)\)
\(=512.2=1024\)
b) \(5^4-2.5^3\)
\(=5^3.5-2.5^3\)
\(=5^3\left(5-2\right)\)
\(=125.3\)
\(=375\)
c) \(2.4^3-4^3.7-6.4^3\)
\(=4^3.\left(2-7-6\right)\)
\(=64.\left(-11\right)=-704\)
d) \(3^2.10^3-\left[13^2-\left(5^2.4+2^2.15\right)\right]\)
\(=9.1000-\left[169-\left(25.4+4.15\right)\right]\)
\(=9000-\left[169-4\left(25+15\right)\right]\)
\(=9000-\left[169-4.40\right]\)
\(=9000-\left[169-160\right]\)
\(=9000-9=8991\)
o0o Ma Kết _ Capricorn o0o trời ơi là trời, thể nào mk thấy nó là lạ!
\(3^2.10^3-\left[13^2\left(5^2.4+2^2.15\right)\right].10^3\)
\(=9.1000-\left[169\left(25.4+4.15\right)\right].1000\)
\(=9000-\left\{169.\left[4\left(25+15\right)\right]\right\}.1000\)
\(=9000-\left\{169.\left[4.40\right]\right\}.1000\)
\(=9000-\left\{169.160\right\}.1000\)
Tự tính tiếp nhé!!
a)
\(\begin{array}{l}\left( {9x - {2^3}} \right):5 = 2\\9x - {2^3} = 2.5\\9x - 8 = 10\\9x = 18\\x = 2\end{array}\)
Vậy \(x = 2\)
b)
\(\begin{array}{l}\left[ {{3^4} - \left( {{8^2} + 14} \right):13} \right]x = {5^3} + {10^2}\\\left[ {81 - \left( {64 + 14} \right):13} \right]x = 125 + 100\\\left[ {81 - 78:13} \right]x = 125 + 100\\\left[ {81 - 6} \right]x = 225\\75x = 225\\x = 3\end{array}\)
Vậy \(x = 3\)
https://dethihsg.com/de-thi-hoc-sinh-gioi-phong-gddt-hoang-hoa-2014-2015/
vào đây gợi ý nhé
k mik đi
@_@
(x2-1)2=9
=> x2-1 = 3
x2 = 3+1
x2 = 4
=> x2 = 4 = 22 ( x2=22 )
<=> x = 2
12:{390:[5.102-(53+x.72)]} = 4
390:[5.102-(53+x.72)] = 12:4
390:[5.102-(53+x.72)] = 3
5.102-(53+x.72) = 390 : 3
5.102-(53+x.72) = 130
=> 500-(125+x+49)=130
125+x+49 = 500-130
125+x+49 = 370
125+x = 370-49
125+x = 321
x = 321-125
x = 106
53(3x+2):13=103:(135:134)
53(3x+2):13=103:13
53(3x+2):13= 1000/13
125(3x+2):13 = 1000/13
125(3x+2) = 1000/13 . 13
125(3x+2) = 1000
3x+2 = 1000:125
3x+2 = 8
3x = 8-2
3x = 6
x = 6:3
x = 2