Giúp mình 3 câu này với
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A new road is being built outside the city
A meeting was being held when it began to rain
A report is being prepared by my friend when the lights go out
\(\Leftrightarrow\dfrac{2\left(3x-1\right)-3\left(x-2\right)-8}{8}>\dfrac{4\left(5-3x\right)}{8}\)
\(\Leftrightarrow2\left(3x-1\right)-3\left(x-2\right)-8>4\left(5-3x\right)\)
\(\Leftrightarrow6x-2-3x+6-8>20-12x\)
\(\Leftrightarrow15x>24\)
\(\Leftrightarrow x>\dfrac{8}{5}\)
Vậy \(S=\left\{x|x>\dfrac{8}{5}\right\}\)
\(\dfrac{3x-1}{4}-\dfrac{3\left(x-2\right)}{8}-1>\dfrac{5-3x}{2}\)
\(\Leftrightarrow\dfrac{2\left(3x-1\right)}{8}-\dfrac{3\left(x-2\right)}{8}-\dfrac{8}{8}>\dfrac{4\left(5-3x\right)}{8}\)
\(\Leftrightarrow6x-2-3x+6-8>20-12x\)
\(\Leftrightarrow3x-4>20-12x\)
\(\Leftrightarrow3x+12x>20+4\)
\(\Leftrightarrow15x>24\)
\(\Leftrightarrow x>\dfrac{8}{5}\)
Vậy...
a.b.\(n_{Fe_2O_3}=\dfrac{48}{160}=0,3mol\)
\(Fe_2O_3+3H_2\rightarrow\left(t^o\right)2Fe+3H_2O\)
0,3 0,9 0,6 0,9 ( mol )
\(m_{Fe}=0,6.56=33,6g\)
\(V_{H_2}=0,9.22,4=20,16l\)
c.\(2H_2+O_2\rightarrow\left(t^o\right)2H_2O\)
0,9 1,8 ( mol )
\(V_{O_2}=0,9.22,4=20,16l\)
câu 4
Zn+2Hcl->ZnCl2+H2
0,1--0,2---------------0,1
n Zn=\(\dfrac{6,5}{65}\)=0,1 mol
=>HCl dư
m HCl=0,05.36,5=1,825g
=>VH2=0,1.22,4=2,24l
bài5
4Al+3O2-to>2Al2O3
0,2----0,15
2KMnO4-to>K2MnO4+MnO2+O2
0,3-------------------------------------0,15
n Al=\(\dfrac{5,4}{27}\)=0,2 mol
VO2=0,15.22,4=3,36l
=>m KMnO4=0,3.158=47,4g
8 We had had some problems, we decided to go on a trip to Hue
9 The students wrote their assignments, they had read some materials
10 After he had watched the football match, he wrote a report