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a) 24.5 - [ 131. ( 13 - 4 )2 ]
=120 - [ 131 . 92 ]
=120 - [ 131 . 81 ]
=120 - 10611
= - 10491
b) 100 : {230:[450−(4−53−52.25)]}
= 100 : \(\left\{230:\left[450-\left(4-125-25.25\right)\right]\right\}\)
= \(100:\left\{230:\left[450-\left(4-125-625\right)\right]\right\}\)
= \(100:\left\{230:\left[450-\left(-746\right)\right]\right\}\)
=\(100:\left\{230:1196\right\}\)
= 100 : \(\dfrac{5}{26}\)= 520
a, \(x:\left[\left(1800+600\right):30\right]=560:\left(315-35\right)\)
\(\Rightarrow\) \(x:\left[2400:30\right]=560:280\)
\(\Rightarrow\) \(x:80=2\)
\(\Rightarrow\) \(x=160\)
b, \(\left[\left(250-25\right):15\right]:x=\left(450-60\right):130\)
\(\Rightarrow\) \(\left[225:15\right]:x=390:130\)
\(\Rightarrow\) \(15:x=3\)
\(\Rightarrow\) \(x=5\)
\(=3\cdot2^3\cdot5^2+2\cdot2^6\cdot2^2\cdot3+2^3\cdot2\cdot3\cdot2^2+3\cdot2\cdot3\cdot2^2\\ =2^3\cdot3\cdot5^2+2^9\cdot3+2^6\cdot3+2^3\cdot3^2\\ =2^3\cdot3\left(5^2+2^6+2^3+3\right)=24\left(25+64+8+3\right)\\ =24\cdot100=2400\)
https://dethihsg.com/de-thi-hoc-sinh-gioi-phong-gddt-hoang-hoa-2014-2015/
vào đây gợi ý nhé
k mik đi
@_@
\(T=\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2008.2010}\)
\(T=2.\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{2008.2010}\right)\)
\(T=2.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{2008}-\frac{1}{2010}\right)\)
\(T=2.\left(\frac{1}{2}-\frac{1}{2010}\right)\)
\(T=2.\frac{502}{1005}=\frac{1004}{1005}\)
\(\Rightarrow T=\frac{1004}{1005}\)
\(A=\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2007.2009}+\frac{1}{2009+2011}\)
\(A=\frac{1}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{2009+2011}\right)\)
\(A=\frac{1}{2}.\left(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{2009}-\frac{1}{2011}\right)\)
\(A=\frac{1}{2}.\left(1-\frac{1}{2011}\right)\)
\(A=\frac{1}{2}.\frac{2010}{2011}\)
\(\Rightarrow A=\frac{1005}{2011}\)
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!!