Rút gọn: (2 - √2).(-5√2) - (3√2 - 5)2
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\(A=2^0+2^1+2^2\)\(+2^3+...+\)\(2^{50}\)
\(2A=2+2^2+2^3+...+2^{51}\)
\(2A-A=A=2^{51}-2^0\)
\(B=5+5^2+5^3+...+5^{99}+5^{100}\)
\(5B=5^2+5^3+5^4+...+5^{100}+5^{101}\)
\(5B-B=4B=5^{101}-5\)
\(B=\frac{5^{101}-5}{4}\)
\(C=3-3^2+3^3-3^4+...+\)\(3^{2007}-3^{2008}+3^{2009}-3^{2010}\)
\(3C=3^2-3^3+3^4-3^5+...-3^{2008}+3^{2009}-3^{2010}+3^{2011}\)
\(3C+C=4C=3^{2011}+3\)
\(C=\frac{3^{2011}+3}{4}\)
\(S_{100}=5+5\times9+5\times9^2+5\times9^3+...+5\times9^{99}\)
\(S_{100}=5\times\left(1+9+9^2+9^3+...+9^{99}\right)\)
\(9S_{100}=5\times\left(9+9^2+9^3+...+9^{99}+9^{100}\right)\)
\(9S_{100}-S_{100}=8S_{100}=5\times\left(9^{100}-1\right)\)
\(S_{100}=\frac{5\times\left(9^{100}-1\right)}{8}\)
a,M=2^0-2^1+2^2-2^3+2^4-2^5+.....+2^2012
2M=2^1-2^2+2^3-2^4+2^5-2^5+......-2^2012+2^2013
3M=2^0+2^2013
M=(2^0+2^2013)÷3
Vậy.......
b,N=3-3^2+3^3-3^4+3^5-3^6+.....+3^2011-3^2012
3N=3^2-3^3+3^4-3^5+3^6-3^7+......+3^2012-3^2013
4N=3-3^2013
N=(3-3^2013)÷4
Vậy........
K tao nhé ko lên lớp tao đánh m😈😈😈
a: \(P=\dfrac{\sqrt{3}\left(2+\sqrt{3}\right)}{\sqrt{3}}+\dfrac{\sqrt{2}\left(\sqrt{2}-1\right)}{1}-\sqrt{3}-\sqrt{2}\)
\(=2+\sqrt{3}+2-\sqrt{2}-\sqrt{3}-\sqrt{2}\)
\(=4-2\sqrt{2}\)
b: \(N=\left(1-\dfrac{\sqrt{5}\left(\sqrt{5}+1\right)}{\sqrt{5}+1}\right)\left(\dfrac{-\sqrt{5}\left(1-\sqrt{5}\right)}{1-\sqrt{5}}-1\right)\)
\(=\left(1-\sqrt{5}\right)\left(-\sqrt{5}-1\right)\)
\(=\left(\sqrt{5}-1\right)\left(\sqrt{5}+1\right)=5-1=4\)
A = 2 ( 3 + 5 ) 2 2 + 3 + 5 + 2 ( 3 − 5 ) 2 2 − 3 − 5 2 3 + 5 4 + ( 5 + 1 ) 2 + 3 − 5 4 − ( 5 − 1 ) 2 = 2 3 + 5 5 + 5 + 3 − 5 5 − 5 2 ( 3 + 5 ) ( 5 − 5 ) + ( 3 − 5 ) ( 5 + 5 ) ( 5 + 5 ) ( 5 − 5 ) = 2 15 − 3 5 + 5 5 − 5 + 15 + 3 5 − 5 5 − 5 25 − 5 = 2. 20 20 = 2 V ậ y A = 2
\(\frac{2^5.7+2^5}{2^5.5^2-2^5.3}=\frac{2^5.\left(7+1\right)}{2^5.\left(5^2-3\right)}=\frac{8}{25-3}=\frac{8}{22}=\frac{4}{11}\)
\(\frac{3^4.5-3^6}{3^4.13+3^4}=\frac{3^4.\left(5-3^2\right)}{3^4.\left(13+1\right)}=\frac{5-9}{14}=\frac{-4}{14}=\frac{-2}{7}\)
\(\frac{-2}{7}=\frac{-22}{77}\)
\(\frac{4}{11}=\frac{28}{77}\)
Ta có: \(\dfrac{3^4\cdot2^3-3^4\cdot4}{3^5\cdot3^2-3^5\cdot5}\)
\(=\dfrac{3^4\cdot\left(2^3-4\right)}{3^5\cdot\left(3^2-5\right)}\)
\(=\dfrac{3^4\cdot4}{3\cdot3^4\cdot4}=\dfrac{1}{3}\)
\(\dfrac{3^4\cdot2^3-3^{\text{4}}\cdot4}{3^5\cdot3^2-3^5\cdot5}\)=\(\dfrac{3^4\left(8-4\right)}{3^5\left(9-5\right)}\)=\(\dfrac{4}{3.4}\)=\(\dfrac{1}{4}\)
Câu 1. 3/2:5/4=? Nhớ rút gọn. Câu 2. Tìm x biết X x 18/5 = 7/10+3/5 nhớ rút gọn thank you các bạn🙏🏻😇
\(\frac{3}{2}:\frac{5}{4}=\frac{3}{2}\times\frac{4}{5}=\frac{12}{20}=\frac{3}{5}\)
X x 18/5 = 7/10 + 3/5
X x 18/5 = 13/10
X = 13/10 : 18/5
X = 13/36
k cho mik với
\(=\dfrac{2\sqrt{2}+\sqrt{10}}{2+\sqrt{5}+1}+\dfrac{2\sqrt{2}-\sqrt{10}}{2-\sqrt{5}+1}\)
\(=\dfrac{\sqrt{2}\left(2+\sqrt{5}\right)\left(3-\sqrt{5}\right)+\sqrt{2}\left(2-\sqrt{5}\right)\left(3+\sqrt{5}\right)}{4}\)
\(=\dfrac{\sqrt{2}\left(6-2\sqrt{5}+3\sqrt{5}-5+6+2\sqrt{5}-3\sqrt{5}-5\right)}{4}\)
\(=\sqrt{2}\cdot\dfrac{2}{4}=\dfrac{1}{\sqrt{2}}\)
\(\left(2-\sqrt{2}\right)\left(-5\sqrt{2}\right)-\left(3\sqrt{2}-5\right)^2\)
\(=-10\sqrt{2}+5-18-5\cdot2\cdot3\sqrt{2}+25\)
\(=-10\sqrt{2}-30\sqrt{2}+12\)
\(=12-40\sqrt{2}\)