\(Rutgonphanso:\frac{10+5}{4+5}\) Va \(\frac{2^2x9}{27x2}\)
VV
Những câu hỏi liên quan
a) \(\frac{6^7}{4^3x9^2}\)
b) \(\frac{12^3x15^3}{4^3x25^2x9^2}\)
c) \(\frac{2^{11}+3x2^{10}}{10x4^5}\)
d) \(\frac{9^4x2-3^6}{34x3^7}\)
a) \(\frac{6^7}{4^3\cdot9^2}=\frac{2^7\cdot3^7}{2^6\cdot3^4}=2\cdot3^3=2\cdot27=54\)
b) \(\frac{12^3\cdot15^3}{4^3\cdot25^2\cdot9^2}=\frac{2^6\cdot3^3\cdot3^3\cdot5^3}{2^6\cdot5^4\cdot3^4}=\frac{3^2}{5}=1,8\)
c) \(\frac{2^{11}+3\cdot2^{10}}{10\cdot4^5}=\frac{2^{10}\left(2+3\right)}{2\cdot5\cdot2^{10}}=\frac{1}{2}=0,5\)
d) \(\frac{3^8\cdot2-3^6}{2\cdot17\cdot3^7}=\frac{3^6\left(3^2\cdot2-1\right)}{2\cdot17\cdot3^7}=\frac{1}{2\cdot3}=\frac{1}{6}\)
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So sánh hai phân số: frac{-7}{31}vafrac{6}{31};frac{-97}{128}vafrac{-99}{128} ;frac{3}{7}vafrac{-6}{7};frac{2}{5}vafrac{4}{5}frac{-2}{5}vafrac{13}{5}frac{4}{9}vafrac{7}{9}frac{5}{12}vafrac{7}{12}frac{-7}{15}vafrac{-8}{15}frac{-2}{5}vafrac{4}{5}frac{4}{7}vafrac{3}{7}frac{-11}{13}vafrac{-15}{13}frac{-2}{7}vafrac{-4}{14}frac{_{-5}}{7}vafrac{-10}{7}frac{-13}{5}vafrac{1}{5}frac{-6}{7}vafrac{-3}{7}frac{3}{7}vafrac{5}{7}frac{-7}{9}vafrac{-5}{9}frac{-3}{7}vafrac{-5}{7}frac{-13}{9}vafrac{1}{9} so sánh số...
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So sánh hai phân số: \(\frac{-7}{31}va\frac{6}{31}\);\(\frac{-97}{128}va\frac{-99}{128}\) ;\(\frac{3}{7}va\frac{-6}{7}\);\(\frac{2}{5}va\frac{4}{5}\)\(\frac{-2}{5}va\frac{13}{5}\)\(\frac{4}{9}va\frac{7}{9}\)\(\frac{5}{12}va\frac{7}{12}\)\(\frac{-7}{15}va\frac{-8}{15}\)\(\frac{-2}{5}va\frac{4}{5}\)\(\frac{4}{7}va\frac{3}{7}\)\(\frac{-11}{13}va\frac{-15}{13}\)\(\frac{-2}{7}va\frac{-4}{14}\)\(\frac{_{-5}}{7}va\frac{-10}{7}\)\(\frac{-13}{5}va\frac{1}{5}\)\(\frac{-6}{7}va\frac{-3}{7}\)\(\frac{3}{7}va\frac{5}{7}\)\(\frac{-7}{9}va\frac{-5}{9}\)\(\frac{-3}{7}va\frac{-5}{7}\)\(\frac{-13}{9}va\frac{1}{9}\) so sánh số cùng mẫu số \(\frac{-7}{13};\frac{-4}{13}\) \(\frac{1}{7};\frac{-4}{-7}\)
left(5+4sqrt{2}right)left(3+2sqrt{1+sqrt{2}}right)left(3-2sqrt{1+sqrt{2}}right) sqrt{frac{9}{4}-sqrt{2}} Sosanh2sqrt{27}vasqrt{147}
2sqrt{15}vasqrt{59}
2sqrt{2}-1va2
frac{sqrt{3}}{2}va1
-frac{sqrt{10}}{2}va-2sqrt{5}
sqrt{6}-1va3
2sqrt{5}-5sqrt{2}va1
frac{sqrt{8}}{3}vafrac{3}{4}
-2sqrt{6}va-sqrt{23}
2sqrt{6}-2va3
sqrt{111}-7va4
Xếp theo thứ tự tăng dần: 21,2sqrt{7},15sqrt{3},-sqrt{123} ; 28sqrt{2},sqrt{14},2sqrt{147},36sqrt{4}
giảm dần: 6sqrt{frac{1}{4}},4sqrt{frac{1}{2}...
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\(\left(5+4\sqrt{2}\right)\left(3+2\sqrt{1+\sqrt{2}}\right)\left(3-2\sqrt{1+\sqrt{2}}\right)\\ \\ \\ \sqrt{\frac{9}{4}-\sqrt{2}}\\ \\ \\ Sosanh2\sqrt{27}va\sqrt{147}\\ \\ \\ 2\sqrt{15}va\sqrt{59}\\ \\ \\ 2\sqrt{2}-1va2\\ \\ \\ \frac{\sqrt{3}}{2}va1\\ \\ \\ -\frac{\sqrt{10}}{2}va-2\sqrt{5}\\ \\ \\ \sqrt{6}-1va3\\ \\ \\ 2\sqrt{5}-5\sqrt{2}va1\\ \\ \\ \frac{\sqrt{8}}{3}va\frac{3}{4}\\ \\ \\ -2\sqrt{6}va-\sqrt{23}\\ \\ \\ 2\sqrt{6}-2va3\\ \\ \\ \sqrt{111}-7va4\)
Xếp theo thứ tự tăng dần: \(21,2\sqrt{7},15\sqrt{3},-\sqrt{123}\) ; \(28\sqrt{2},\sqrt{14},2\sqrt{147},36\sqrt{4}\)
giảm dần: \(6\sqrt{\frac{1}{4}},4\sqrt{\frac{1}{2}},-\sqrt{132},2\sqrt{3},\sqrt{\frac{15}{5}}\); \(-27,4\sqrt{3},16\sqrt{5},21\sqrt{2}\)
a,\(\left(5+4\sqrt{2}\right)\left(3+2\sqrt{1+\sqrt{2}}\right)\left(3-2\sqrt{1+\sqrt{2}}\right)\)
=\(\left(5+4\sqrt{2}\right)\left(9-4\left(1+\sqrt{2}\right)\right)\)
=\(\left(5+4\sqrt{2}\right)\left(9-4-4\sqrt{2}\right)\)
=\(\left(5+4\sqrt{2}\right)\left(5-4\sqrt{2}\right)=25-\left(4\sqrt{2}\right)^2\)
=-7
b, \(\sqrt{\frac{9}{4}-\sqrt{2}}=\sqrt{\frac{9-4\sqrt{2}}{4}}=\frac{\sqrt{9-4\sqrt{2}}}{2}=\frac{\sqrt{9-2\sqrt{8}}}{2}=\frac{\sqrt{\left(\sqrt{8}-1\right)^2}}{2}=\frac{\left|\sqrt{8}-1\right|}{2}=\frac{\sqrt{8}-1}{2}\)
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So sánh:
1) \(2\sqrt{27}\) và \(\sqrt{147}\)
+ \(2\sqrt{27}\) = \(6\sqrt{3}\)
+ \(\sqrt{147}\) = \(7\sqrt{3}\)
⇒ \(6\sqrt{3}\) < \(7\sqrt{3}\)
Vậy: \(2\sqrt{27}\)< \(\sqrt{147}\)
2) \(2\sqrt{15}\) và \(\sqrt{59}\)
+ \(2\sqrt{15}\) = \(\sqrt{60}\)
⇒ \(\sqrt{60}\) > \(\sqrt{59}\)
Vậy: \(2\sqrt{15}\) > \(\sqrt{59}\)
3) \(2\sqrt{2}-1\) và 2
\(giống\left(-1\right)\left\{{}\begin{matrix}3-1\\2\sqrt{2}-1\end{matrix}\right.\)
So sánh: 3 và \(2\sqrt{2}\)
+ 3 = \(\sqrt{9}\)
+ \(2\sqrt{2}=\sqrt{8}\)
⇒ \(\sqrt{8}\) < \(\sqrt{9}\)
⇒ \(\sqrt{8}\) -1 < \(\sqrt{9}\) -1
⇒ \(2\sqrt{2}\) - 1 < 3 - 1
Vậy: \(2\sqrt{2}-1< 2\)
4) \(\frac{\sqrt{3}}{2}\) và 1
+ 1 = \(\frac{2}{2}\)
⇒ \(\frac{\sqrt{3}}{2}\) < \(\frac{2}{2}\)
Vậy: \(\frac{\sqrt{3}}{2}\) < 1
5) \(\frac{-\sqrt{10}}{2}\) và \(-2\sqrt{5}\)
+ \(-2\sqrt{5}\) = \(\frac{-4\sqrt{5}}{2}\) = \(\frac{-\sqrt{80}}{2}\)
⇒ \(\frac{-\sqrt{10}}{2}\) > \(\frac{-\sqrt{80}}{2}\)
Vậy: \(\frac{-\sqrt{10}}{2}\) > \(-2\sqrt{5}\)
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\(\frac{1}{2}-\frac{1}{3}-\frac{2}{3}+\frac{1}{4}+\frac{2}{4}+\frac{3}{4}-\frac{1}{5}-\frac{2}{5}-\frac{3}{5}-\frac{4}{5}+...+\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+...+\frac{9}{10}\)\(+\)\(\frac{9}{10}\)
Đề bài là gì bạn ơi có chỗ ...
chưa có đề bạn ơi! Y_Y
Hok tốt ^_^
Quy luật của dãy số này là gì bạn có thể nói rõ ra đc ko
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Bài 1: Sắp xếp các phân số sau theo thứ tự:a) Tăng dần: frac{-5}{6};frac{7}{8};frac{7}{24};frac{16}{17};frac{-3}{4};frac{2}{3}b) Giảm dần: frac{-5}{8};frac{7}{10};frac{-16}{19};frac{20}{23};frac{214}{315};frac{205}{107}Bài 2: So sánh hai phân số:a) frac{102}{97}vafrac{99}{101}b)frac{-5}{14}vafrac{-4}{11}
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Bài 1: Sắp xếp các phân số sau theo thứ tự:
a) Tăng dần: \(\frac{-5}{6};\frac{7}{8};\frac{7}{24};\frac{16}{17};\frac{-3}{4};\frac{2}{3}\)
b) Giảm dần: \(\frac{-5}{8};\frac{7}{10};\frac{-16}{19};\frac{20}{23};\frac{214}{315};\frac{205}{107}\)
Bài 2: So sánh hai phân số:
a) \(\frac{102}{97}va\frac{99}{101}\)
b)\(\frac{-5}{14}va\frac{-4}{11}\)
Tính \(\frac{1}{2}-\frac{1}{3}-\frac{2}{3}+\frac{1}{4}+\frac{2}{4}+\frac{3}{4}-\frac{1}{5}-\frac{2}{5}-\frac{3}{5}-\frac{4}{5}+...+\frac{1}{10}+...+\frac{9}{10}\)
Đặt A = 1/2 - 1/3 - 2/3 + 1/4 + 2/4 + 3/4 - 1/5 - 2/5 - 3/5 - 4/5 + ... + 1/10 + ...+ 9/10
A = 1/2 - ( 1/3 + 2/3) + (1/4 + 2/4 + 3/4) - ( 1/5 + 2/5 + 3/5 + 4/5) + ( 1/6 + 2/6 + ... + 5/6) - ( 1/7 + 2/7 + ... + 6/7) + ( 1/8 + 2/8 + ... + 7/8) - ( 1/9 + 2/9 + ... + 8/9)
A = 1/2 - 1 + [( 1/4 + 3/4) + 2/4] - [(1/5 + 4/5) + (2/5 + 3/5)] + [(1/6+5/6) + ( 2/6 + 4/6) + 3/6] - [(1/7 + 6/7) + (2/7 + 5/7) + (3/7 + 4/7)] + [(1/8 + 7/8) + (2/8 + 6/8) + (3/8 + 5/8) + 4/8)] - [(1/9 + 8/9) + (2/9 + 7/9) + (3/9 + 6/9) + (4/9 + 5/9)] + [(1/10 + 9/10) + ( 2/10 + 8/10) + ( 3/10 + 7/10) + ( 4/10 + 6/10) + 5/10]
A = 1/2 - 1 + ( 1 + 1/2) - 2 + ( 2 + 1/2) - 3 + ( 3 + 1/2) - 4 + ( 4 + 1/2)
A = 1/2 + 1/2 + 1/2 + 1/2 + 1/2
A = 1/2 × 5 = 5/2
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Đặt A = 1/2 - 1/3 - 2/3 + 1/4 + 2/4 + 3/4 - 1/5 - 2/5 - 3/5 - 4/5 + ... + 1/10 + ...+ 9/10
A = 1/2 - ( 1/3 + 2/3) + (1/4 + 2/4 + 3/4) - ( 1/5 + 2/5 + 3/5 + 4/5) + ( 1/6 + 2/6 + ... + 5/6) - ( 1/7 + 2/7 + ... + 6/7) + ( 1/8 + 2/8 + ... + 7/8) - ( 1/9 + 2/9 + ... + 8/9)
A = 1/2 - 1 + [( 1/4 + 3/4) + 2/4] - [(1/5 + 4/5) + (2/5 + 3/5)] + [(1/6+5/6) + ( 2/6 + 4/6) + 3/6] - [(1/7 + 6/7) + (2/7 + 5/7) + (3/7 + 4/7)] + [(1/8 + 7/8) + (2/8 + 6/8) + (3/8 + 5/8) + 4/8)] - [(1/9 + 8/9) + (2/9 + 7/9) + (3/9 + 6/9) + (4/9 + 5/9)] + [(1/10 + 9/10) + ( 2/10 + 8/10) + ( 3/10 + 7/10) + ( 4/10 + 6/10) + 5/10]
A = 1/2 - 1 + ( 1 + 1/2) - 2 + ( 2 + 1/2) - 3 + ( 3 + 1/2) - 4 + ( 4 + 1/2)
A = 1/2 + 1/2 + 1/2 + 1/2 + 1/2
A = 1/2 × 5 = 5/2
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\(\frac{x}{2}\)=\(\frac{y}{3}\);\(\frac{y}{4}\)=\(\frac{z}{5}\) va x+y-z=10
Tính nhanh:Afrac{1}{6x10}+frac{1}{10x14}+frac{1}{14x18}+frac{1}{18x22}+frac{1}{22x26}+frac{1}{26x30}Bfrac{5}{2x3}+frac{5}{3x4}+frac{5}{4x5}+...+frac{5}{8x9}Cleft(frac{7^2}{2x9}+frac{7^2}{9x16}+...+frac{7^2}{65x72}right):left(frac{1}{3}-frac{7}{36}right)Dfrac{2}{2x3x4}+frac{2}{3x4x5}+...+frac{2}{37x38x39}+frac{2}{38x39x40}Efrac{202202}{1212}+frac{202202}{2020}+frac{202202}{3030}+frac{202202}{4242}+frac{202202}{5656}Nhanh lên nha!Ngày mai mik đi học rồi!
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Tính nhanh:
A=\(\frac{1}{6x10}+\frac{1}{10x14}+\frac{1}{14x18}+\frac{1}{18x22}+\frac{1}{22x26}+\frac{1}{26x30}\)
B=\(\frac{5}{2x3}+\frac{5}{3x4}+\frac{5}{4x5}+...+\frac{5}{8x9}\)
C=\(\left(\frac{7^2}{2x9}+\frac{7^2}{9x16}+...+\frac{7^2}{65x72}\right):\left(\frac{1}{3}-\frac{7}{36}\right)\)
D=\(\frac{2}{2x3x4}+\frac{2}{3x4x5}+...+\frac{2}{37x38x39}+\frac{2}{38x39x40}\)
E=\(\frac{202202}{1212}+\frac{202202}{2020}+\frac{202202}{3030}+\frac{202202}{4242}+\frac{202202}{5656}\)
Nhanh lên nha!Ngày mai mik đi học rồi!
\(A=\frac{1}{6.10}+\frac{1}{10.14}+\frac{1}{14.18}+\frac{1}{18.22}+\frac{1}{22.26}+\frac{1}{26.30}\)
\(=\frac{1}{4}.\left(\frac{1}{6}-\frac{1}{10}+\frac{1}{10}-\frac{1}{14}+\frac{1}{14}-\frac{1}{18}+\frac{1}{18}-\frac{1}{22}+\frac{1}{22}-\frac{1}{26}+\frac{1}{26}-\frac{1}{30}\right)\)
\(=\frac{1}{4}.\left(\frac{1}{6}-\frac{1}{30}\right)=\frac{1}{4}.\frac{2}{15}=\frac{1}{30}\)
\(B=\frac{5}{2.3}+\frac{5}{3.4}+\frac{5}{4.5}+...+\frac{5}{8.9}\)\(=5.\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{8.9}\right)\) \(=5.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{8}-\frac{1}{9}\right)\)
\(=5.\left(\frac{1}{2}-\frac{1}{9}\right)=5.\frac{7}{18}=\frac{35}{18}\)
\(C=\left(\frac{7^2}{2.9}+\frac{7^2}{9.16}+....+\frac{7^2}{65.72}\right):\left(\frac{1}{3}-\frac{7}{36}\right)\)
\(=7.\left(\frac{7}{2.9}+\frac{7}{9.16}+...+\frac{7}{65.72}\right):\frac{5}{36}\) \(=7.\left(\frac{1}{2}-\frac{1}{9}+\frac{1}{9}-\frac{1}{16}+...+\frac{1}{65}-\frac{1}{72}\right):\frac{5}{36}\)'
\(=7.\left(\frac{1}{2}-\frac{1}{72}\right):\frac{5}{36}=7.\frac{35}{72}:\frac{5}{36}=\frac{49}{2}\)
\(D=\frac{2}{2.3.4}+\frac{2}{3.4.5}+...+\frac{2}{37.38.39}+\frac{2}{38.39.40}\)
\(=2.\left(\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{37.38.39}+\frac{1}{38.39.40}\right)\)
\(=2.\frac{1}{2}.\left(\frac{1}{2.3}-\frac{1}{3.4}+\frac{1}{3.4}-\frac{1}{4.5}+...+\frac{1}{37.38}-\frac{1}{38.39}+\frac{1}{38.39}-\frac{1}{39.40}\right)\)
\(=\frac{1}{2.3}-\frac{1}{39.40}=\frac{259}{1560}\)
\(E=\frac{202202}{1212}+\frac{202202}{2020}+\frac{202202}{3030}+\frac{202202}{4242}+\frac{202202}{5656}\)
\(=202202.\left(\frac{1}{3.4.101}+\frac{1}{4.5.101}+\frac{1}{5.6.101}+\frac{1}{6.7.101}+\frac{1}{7.8.101}\right)\)
\(=2002.\left(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}\right)\)
\(=2002.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}\right)\)
\(=2002.\left(\frac{1}{3}-\frac{1}{8}\right)=2002.\frac{5}{24}=\frac{5005}{12}\)
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tim x,y,z khi
\(\frac{x}{7}=\frac{y}{3}va\)x-24=y
\(\frac{x}{5}=\frac{y}{7}=\frac{z}{2}\)va y-x=48
\(\frac{x}{2}=\frac{y}{3};\frac{y}{4}=\frac{z}{5}\)va x-y- z=28
\(\frac{x}{3}=\frac{y}{5}=\frac{z}{7}\)va 2x+3-z=-14
Mình làm 1 phép thôi nha những phép còn lại bạn tự nghĩ nhé !
\(\frac{x}{7}=\frac{y}{3}\) và \(x-24=y\)'
Ta có : \(x-24=y\) hay cũng có thể viết \(x-y=24\)
Ta lại có : \(\frac{x}{7}=\frac{y}{3}\)
Áp dụng tính chất của dãy tỉ số bằng nhau nên ta được :
\(\frac{x}{7}=\frac{y}{3}=\frac{x-y}{7-3}=\frac{24}{4}=6\) ( vì \(x-y=24\) )
\(\Rightarrow\frac{x}{7}=6\Rightarrow x=6\cdot7\Rightarrow x=42\)
\(\Rightarrow\frac{y}{3}=6\Rightarrow y=6\cdot3\Rightarrow y=18\)
Vậy \(x=42\) và \(y=18\)
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