Câu 1 mng làm từ câu i trở xuống cũng được ạ. Em tha thiết xin mng luôn í :((
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1:
i: \(=\dfrac{15}{34}+\dfrac{19}{34}+\dfrac{7}{21}+\dfrac{2}{3}-1-\dfrac{15}{37}\)
\(=1+\dfrac{1}{3}+\dfrac{2}{3}-1-\dfrac{15}{37}\)
\(=1-\dfrac{15}{37}=\dfrac{22}{37}\)
j: \(=1-\left(-27\right)+\dfrac{1}{2}:\dfrac{-1}{8}\)
\(=1+27-4=24\)
k: \(=-8+\dfrac{1}{2}\cdot\dfrac{-4}{1}-15\)
\(=-8-2-15=-25\)
l: \(=3:\dfrac{9}{4}+\dfrac{1}{9}\cdot6\)
\(=3\cdot\dfrac{4}{9}+\dfrac{1}{9}\cdot6\)
\(=\dfrac{4}{3}+\dfrac{2}{3}=2\)
m: \(=9\cdot\dfrac{1}{3}-\left(-27\right)=3+27=30\)
n: \(\sqrt{\dfrac{16}{25}}\cdot\sqrt{\dfrac{121}{64}}-1\dfrac{3}{10}\)
\(=\dfrac{4}{5}\cdot\dfrac{11}{8}-\dfrac{13}{10}\)
\(=\dfrac{11}{10}-\dfrac{13}{10}=-\dfrac{2}{10}=-\dfrac{1}{5}\)
o: \(=\dfrac{9}{8}\cdot12-\dfrac{1}{2}\)
\(=\dfrac{27}{2}-\dfrac{1}{2}=\dfrac{26}{2}=13\)
p: \(=\dfrac{3^2\cdot2^2+3^2\cdot3\cdot2^2+3^2}{-13}\)
\(=\dfrac{3^2\left(2^2+3\cdot2^2+3^2\right)}{-13}\)
\(=\dfrac{9\cdot\left(4+3\cdot4+9\right)}{-13}\)
\(=\dfrac{9\cdot25}{-13}=-\dfrac{225}{13}\)
mình làm những bài bn chưa lm nhé
9B
10A
bài 2
have repainted
bàii 3
ride - walikking
swimming
watch
1. should ask
*must not ask là sai vì người quản lí mới nên hỏi vài câu hỏi trước khi thực hiện thay đổi
*have to ask (mang tính chủ quan) nên có làm hay không làm cũng được nên ta không chọn đáp án này
2. could prevent
Vì sau would, could là V_inf
1. illegal
2. traffic jam
3. seatbelt
4. safely
5. railway station
6. safety
7. traffic signs
8. helicopter
9. tricycle
10. boat
bạn đang hỏi về % khối lượng của gì ạ? Nếu mà là của các nguyên tố trong hợp chất này thì cả 2 nguyên tử C và O đều không có khối lượng % như vậy nhé .-.
\(K.L.P.T_{CO_2}=12+16.2=44< amu>.\)
\(\%C=\dfrac{12.100}{44}\approx27,27\%.\)
\(\%O=\dfrac{16.2.100}{44}\approx72,73\%.\)
câu 1 làm từ câu i cũng được ạ








Câu 1:
a: \(\frac37+\left(-\frac52\right)+\frac35\)
\(=\frac37-\frac52+\frac35\)
\(=\frac{30}{70}-\frac{175}{70}+\frac{42}{70}=\frac{30+42-175}{70}=-\frac{103}{70}\)
b: \(0,8-\left(-\frac27\right)-\frac{7}{10}=\frac45+\frac27-\frac{7}{10}\)
\(=\frac{56}{70}+\frac{20}{70}-\frac{49}{70}=\frac{56+20-49}{70}=\frac{56-29}{70}=\frac{27}{70}\)
c: \(\frac34-\left\lbrack\left(-\frac53\right)-\left(\frac{1}{12}+\frac29\right)\right\rbrack\)
\(=\frac34+\frac53+\frac{1}{12}+\frac29\)
\(=\frac{27}{36}+\frac{60}{36}+\frac{3}{36}+\frac{8}{36}=\frac{98}{36}=\frac{49}{18}\)
d: \(19\frac13\cdot\frac45-\frac45\cdot15\frac13\)
\(=\frac45\left(19+\frac13-15-\frac13\right)\)
\(=\frac45\cdot4=\frac{16}{5}\)
e: \(\frac38\cdot\left(-\frac{3}{11}\right)+\frac38\cdot\left(-\frac{8}{11}\right)+2\frac57\)
\(=\frac38\left(-\frac{3}{11}-\frac{8}{11}\right)+2+\frac57\)
\(=-\frac38+2+\frac57=\frac{13}{8}+\frac57=\frac{91}{56}+\frac{40}{56}=\frac{131}{56}\)
f: \(\left(-\frac{5}{11}:\frac{13}{8}-\frac{5}{11}:\frac{13}{3}\right)-\left|-\frac{1}{33}\right|\)
\(=-\frac{5}{11}\cdot\frac{8}{13}-\frac{5}{11}\cdot\frac{3}{13}-\frac{1}{33}\)
\(=-\frac{5}{11}\cdot\frac{11}{13}-\frac{1}{33}=-\frac{5}{13}-\frac{1}{33}=\frac{-165-13}{13\cdot33}=\frac{-178}{429}\)
g: \(\frac{4}{23}+\frac{5}{21}+\frac12-\frac{4}{23}+\frac{16}{21}\)
\(=\left(\frac{4}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+\frac12\)
\(=1+\frac12=\frac32\)
h: \(\frac{13}{25}+\frac{6}{41}+\frac{-38}{25}+\frac{35}{41}-0,5\)
\(=\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-0,5\)
\(=-\frac{25}{25}+\frac{41}{41}-0,5=-0,5\)
i: \(\frac{15}{34}+\frac{7}{21}+\frac{19}{34}-1\frac{15}{17}+\frac23\)
\(=\left(\frac{15}{34}+\frac{19}{34}\right)+\left(\frac13+\frac23\right)-1-\frac{15}{17}\)
\(=1+1-1-\frac{15}{17}=1-\frac{15}{17}=\frac{2}{17}\)
j: \(\left(\frac{2022}{2023}\right)^0-\left(-3\right)_{}^3+\frac12:\left(-\frac12\right)^3\)
\(=1-\left(-27\right)+\frac12:\frac{-1}{8}\)
=28-4
=24
k: \(\left(-2\right)^3+\frac12:\frac{-1}{4}-\left|15\right|\)
\(=-8+\frac12\cdot\left(-4\right)-15\)
=-8-2-15
=-25
l: \(3:\left(-\frac32\right)^2+\frac19\cdot\sqrt{36}\)
\(=3:\frac94+\frac19\cdot6=3\cdot\frac49+\frac69=\frac{12}{9}+\frac69=\frac{18}{9}\)
=2
m: \(\sqrt{81}\cdot\frac13-\left(-3\right)^3=9\cdot\frac13-\left(-27\right)\)
=3+27
=30
n: \(\sqrt{\frac{16}{25}}\cdot\sqrt{\frac{121}{64}}-1\frac{3}{10}\)
\(=\frac45\cdot\frac{11}{8}-\frac{13}{10}\)
\(=\frac{11}{10}-\frac{13}{10}=-\frac{2}{10}=-\frac15\)
o: \(\frac{3^2}{2^3}\cdot\sqrt{144}-50\%\)
\(=\frac98\cdot12-\frac12=9\cdot\frac32-\frac12=\frac{27}{2}-\frac12=\frac{26}{2}\)
=13
p: \(\frac{6^2+3\cdot6^2+3^2}{-13}\)
\(=\frac{36+3\cdot108+9}{-13}=\frac{45+324}{-13}=\frac{369}{-13}=-\frac{369}{13}\)
q: \(\frac{5^4\cdot20^4}{25^5\cdot4^5}=\frac{\left(5\cdot20\right)^4}{\left(25\cdot4\right)^5}=\frac{100^4}{100^5}=\frac{1}{100}\)
r: \(\frac{4^6\cdot9^5+6^9\cdot120}{8^4\cdot3^{12}-6^{11}}\)
\(=\frac{2^{12}\cdot3^{10}+2^9\cdot3^9\cdot2^3\cdot3\cdot5}{2^{12}\cdot3^{12}-2^{11}\cdot3^{11}}\)
\(=\frac{2^{12}\cdot3^{10}+2^{12}\cdot3^{10}\cdot5}{2^{11}\cdot3^{11}\left(2\cdot3-1\right)}=\frac{2^{12}\cdot3^{10}\left(1+5\right)}{2^{11}\cdot3^{11}\cdot5}=\frac23\cdot\frac65=\frac{12}{15}=\frac45\)