1. tính nhanh
0,9x458x2x0,18x2520+0,5
3,54x72+0,23x25+3,54x27+0,17x25
2. tìm x
13,8:(5,6xx)-1,25=1,75
(4,578x3+5,422xx):1,2-1,2=23,8
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Giải
a) ( 792,81.0,25 + 792,81.0,75 ).( 11.9 - 900.0,1 - 9 )
= ( 792,81.0,25 + 792,81.0,75 ).9.(11 - 100.0,1 - 1 )
= ( 792,81.0,25 + 792,81.0,75 ).9.0
= 0
b) 3,54.73 + 0,23.25 + 3,54.27 + 0,17.25
= ( 3,54.73 + 3,54.27 ) + ( 0,23.25 + 0,17.25 )
= 3,54.( 73 + 27 ) + 25.( 0,23 + 0,17 )
= 3,54.100 + 25.0,4
= 354 + 10
= 364
\(a,=\left(1,2\right)^{20}:\left(1,2\right)^{17}=\left(1,2\right)^3=\dfrac{216}{125}\\ b,=\left(-1,25\right)^5\cdot\left(-1,25\right)^4=\left(-1,25\right)^9=\left(-\dfrac{4}{3}\right)^9=...\)
\(1.m_{Cu}=1,2.64=76,8\left(g\right)\\ 2.m_{NaCl}=1,25.58,5=73,125\\ 3.n_{C_6H_{12}O_6}=\dfrac{7,2.10^{23}}{6.10^{23}}=1,2\left(mol\right)\\ \Rightarrow m_{C_6H_{12}O_6}=1,2.180=216\left(g\right)\\ 4.n_{O_2}=3,6.32=115,2\left(g\right)\\ 5.n_{O_2}=\dfrac{1,2.10^{23}}{6.10^{23}}=0,2\left(mol\right)\\ \Rightarrow m_{O_2}=0,2.32=6,4\left(g\right)\\ 6.n_{N_2}=\dfrac{26,88}{22,4}=1,2\left(mol\right)\\ \Rightarrow m_{N_2}=1,2.28=33,6\left(g\right)\\ 7.n_{CO_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\\ \Rightarrow m_{CO_2}=0,5.44=22\left(g\right)\\ 8.n_{H_2}=\dfrac{31,36}{22,4}=1,4\left(mol\right)\\ \Rightarrow m_{H_2}=1,4.2=2,8\left(g\right)\)
\(1,m_{Cu}=1,2\cdot64=76,8\left(g\right)\\ 2,m_{NaCl}=1,25\cdot58,5=73,125\left(g\right)\\ 3,n_{C_6H_{12}O_6}=\dfrac{7,2\cdot10^{-23}}{6\cdot10^{-23}}=1,2\left(mol\right)\\ \Rightarrow m_{C_6H_{12}O_6}=1,2\cdot180=216\left(g\right)\\ 4,m_{O_2}=3,6\cdot32=115,2\left(g\right)\\ 5,n_{O_2}=\dfrac{1,2\cdot10^{-23}}{6\cdot10^{-23}}=0,2\left(mol\right)\\ \Rightarrow m_{O_2}=0,2\cdot32=6,4\left(g\right)\\ 6,n_{N_2}=\dfrac{26,88}{22,4}=1,2\left(mol\right)\\ \Rightarrow m_{N_2}=1,2\cdot28=33,6\left(g\right)\\ 7,n_{CO_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\\ \Rightarrow m_{CO_2}=0,5\cdot44=22\left(g\right)\\ 8,n_{H_2}=\dfrac{31,36}{22,4}=1,4\left(mol\right)\\ \Rightarrow m_{H_2}=1,4\cdot2=2,8\left(g\right)\)
tính nhanh:(1,25-0,25*5)*(1,1*1,2*1,3*1,4*1,5)=0x(1,1x1,2x1,3x1,4x1,5)
=0
k nha
๖ۣۜH๖ۣۜU๖ۣۜY ๖ۣۜR๖ۣۜI๖ۣۜO
(1,25-0,25x5)x(1,1x1,2x1,3x1,4x1,5)=(1,25-1,25)x(1,1x1,2x1,3x1,4x1,5)=0x(1,1x1,2x1,3x1,4x1,5)=0
Bn ơi bn viết rõ ràng ra đi, mk ko hỉu j hét, hoa mắt lun