\(\left|\right|^{ }\)
Những câu hỏi liên quan
Tính bằng cách hợp lí :
\(A=\left(-5,85\right)+\left\{\left[\left(+41,3\right)+\left(+5\right)\right]+\left(+0,85\right)\right\}\)
\(B=\left(-87,5\right)+\left\{\left(+87,5\right)+\left[\left(+3,8\right)+\left(-0,8\right)\right]\right\}\)
\(C=\left[\left(+9,8\right)+\left(-13\right)\right]+\left[\left(-5\right)+\left(+8,5\right)\right]\)
\(A=\left(-5,85\right)+\left\{\left[\left(+41,3\right)+\left(+5\right)\right]+\left(+0,85\right)\right\}\)
\(A=\left(-5,85\right)+\left\{\left[41,3+5\right]+0,85\right\}\)
\(A=\left(-5,85\right)+\left\{41,3+5+0,85\right\}\)
\(A=\left(-5,85\right)+\left\{41,3+5,85\right\}\)
\(A=\left(-5,85\right)+41,3+5,85\)
\(A=\left(-5,85\right)+5,85+41,3\)
\(A=0+41,3\)
\(A=41,3\)
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\(B=\left(-87,5\right)+\left\{\left(+87,5\right)+\left[\left(+3,8\right)+\left(-0,8\right)\right]\right\}\)
\(B=\left(-87,5\right)+87,5+3,8+\left(-0,8\right)\)
\(B=\left[\left(-87,5\right)+87,5\right]+\left[3,8+\left(-0,8\right)\right]\)
\(B=0+3\)
\(B=3\)
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\(C=\left[\left(+9,8\right)+\left(-13\right)\right]+\left[\left(-5\right)+\left(+8,5\right)\right]\)
\(C=\left(-3,2\right)+3,5\)
\(C=0,3\)
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\(7-\left\{12-\left[-\left(-3\right)+\left(-10\right)-\left(-11\right)\right]-\left[-\left(-9\right)+\left(-8\right)-\left(+12\right)\right]\right\}-\left(-4\right)\)
\(7-\left\{12-\left[-\left(-3\right)+\left(-10\right)-\left(-11\right)\right]-\left[-\left(-9\right)+\left(-8\right)-12\right]\right\}\)\(-\left(-4\right)\)
= \(7-\left\{12-\left[3+\left(-10\right)+11\right]-\left[9+\left(-8\right)-12\right]\right\}\) \(+4\)
= \(7-\left\{12-\left[7+11\right]-\left[1-12\right]\right\}+4\)
= \(7-\left\{12-18-\left(-11\right)\right\}+4\)
= \(7-\left\{-6+11\right\}+4\)
= \(7-5+4\)
= 6
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7 - { 12 - [ - (- 3) + (- 10) - (- 11) ] - [ - (- 9) + (- 8) - (+ 12) ] } - (- 4)
= 7 - [ 12 - ( 3 - 10 + 11 ) - ( 9 - 8 - 12 ) ] + 4
= 7 - ( 12 - 4 + 11 ) + 4
=7 - 19 + 4
= - 8
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Tính :\(-5-\left\{-\left[-\left(-7\right)+\left(-10\right)\right]-\left[5-\left(-12\right)\right]\right\}-\left[\left(-3\right)-\left(-9\right)-\left(+4\right)-5\right]\)
Tính bằng cách hợp lí giá trị của các biểu thức sau :
a) left(-3,8right)+left[left(-5,7right)+left(+3,8right)right]
b) left(+31,4right)+left[left(+6,4right)+left(-18right)right]
c) left[left(-9,6right)+left(+4,5right)right]+left[left(+9,6right)+left(-1,5right)right]
d) left[left(-4,9right)+left(-37,8right)right]+left[left(+1,9right)+left(+2,8right)right]
Đọc tiếp
Tính bằng cách hợp lí giá trị của các biểu thức sau :
a) \(\left(-3,8\right)+\left[\left(-5,7\right)+\left(+3,8\right)\right]\)
b) \(\left(+31,4\right)+\left[\left(+6,4\right)+\left(-18\right)\right]\)
c) \(\left[\left(-9,6\right)+\left(+4,5\right)\right]+\left[\left(+9,6\right)+\left(-1,5\right)\right]\)
d) \(\left[\left(-4,9\right)+\left(-37,8\right)\right]+\left[\left(+1,9\right)+\left(+2,8\right)\right]\)
a)
\(\left(-3,8\right)+\left[\left(-5,7\right)+\left(+3,8\right)\right]\\ =\left(-3,8\right)+\left(-5,7\right)+3,8\\ =\left[\left(-3,8\right)+3,8\right]+\left(-5,7\right)\\ =0+\left(-5,7\right)\\ =-5,7\)
b)
\(\left(+31,4\right)+\left[\left(+6,4\right)+\left(-18\right)\right]\\ =31,4+6,4-18\\ =37,8-18\\ =19,8\)
c)
\(\left[\left(-9,6\right)+\left(+4,5\right)\right]+\left[\left(+9,6\right)+\left(-1,5\right)\right]\\ =\left(-9,6\right)+4,5+9,6-1,5\\ =\left[\left(-9,6\right)+9,6\right]+\left[4,5-1,5\right]\\ =0+3\\ =3\)
d)
\(\left[\left(-4,9\right)+\left(-37,8\right)\right]+\left[\left(+1,9\right)+\left(+2,8\right)\right]\\ =\left(-4,9\right)-37,8+1,9+2,8\\ =\left[\left(-4,9+1,9\right)\right]-\left[\left(37,8-2,8\right)\right]\\ =\left(-3\right)-35\\ =-38\)
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a)(-3,8)+[(-5,7)+3,8]
=(-3,8)+(-5,7)+3,8
=(-3,8)+3,8+(-5,7)
=0+(-5,7)
=-5,7
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a. (-3,8) + [(-5,7) + ( +3,8)] = [(-3,8) + (+3,8)] + (-5,7)
= 0 + (-5,7) = -5,7
b. (+31,4) + [(+6,4) + (-18)] = [(+31,4) + (-18)] + (+6,4)
= (+13,4) + ( +6,4) =19,8
c. [(-9,6) + (+4,5)] + [(+9,6) + (-1,5)] = [(=9,6) + (+9,6)] + [(+4,5) + (-1,5)]
= 0 + 3
d. [(-4,9) + (-37,8)] + [(+1,9) + (+2,8)] = [(-4,9) + (+1,9)] + [( -37,8) + ( + 2,8)]
= (-3) + ( -35) = -38
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i, \(\left(x-1\right)\left(x+3\right)-\left(x-1\right)\left(2x+1\right)=0\)
k, \(\left(x+2\right)\left(x+1\right)-\left(x-3\right)\left(x+2\right)=0\)
l, \(\left(x-2\right)\left(x+3\right)=\left(x-2\right)\left(2x+5\right)\)
\(\left(x-1\right)\left(-x+2\right)=0\Leftrightarrow x=1;x=2\)
\(\left(x+2\right)\left(x+1-x+3\right)=0\Leftrightarrow x=-2\)
\(\left(x-2\right)\left(x+3\right)-\left(x-2\right)\left(2x+5\right)=0\Leftrightarrow\left(x-2\right)\left(-x-2\right)=0\Leftrightarrow x=-2;x=2\)
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\(i,\left(x-1\right)\left(x+3\right)-\left(x-1\right)\left(2x+1\right)=0\\ \Leftrightarrow\left(x-1\right)\left(x+3-2x-1\right)=0\\ \Leftrightarrow\left(x-1\right)\left(-x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\\ k,\left(x+2\right)\left(x+1\right)-\left(x-3\right)\left(x+2\right)=0\\ \Leftrightarrow\left(x+2\right)\left(x+1-x+3\right)=0\\ \Leftrightarrow4\left(x+2\right)=0\\ \Leftrightarrow x+2=0\\ \Leftrightarrow x=-2\\ l,\left(x-2\right)\left(x+3\right)=\left(x-2\right)\left(2x+5\right)\\ \Leftrightarrow\left(x-2\right)\left(2x+5\right)-\left(x-2\right)\left(x+3\right)=0\\ \Leftrightarrow\left(x-2\right)\left(2x+5-x-3\right)=0\\ \Leftrightarrow\left(x-2\right)\left(x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
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Câu 1 ) A / Mg(NO3) underrightarrow{left(1right)} Mg(OH)2 underrightarrow{left(2right)} MgCl2underrightarrow{left(3right)} KCl underrightarrow{left(4right)} KNO3
B/ Naunderrightarrow{left(1right)}Na_2Ounderrightarrow{left(2right)}NaOHunderrightarrow{left(3right)}Na_2SO_4underrightarrow{left(4right)}NaClunderrightarrow{left(5right)}NaNO_3underrightarrow{left(6right)}NaClunderrightarrow{left(7right)}NaOH
C/Mgunderrightarrow{left(1right)}MgOunderrightarrow{left(2right)}MgCl_2underrightarrow{left...
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Câu 1 ) A / Mg(NO3) \(\underrightarrow{\left(1\right)}\) Mg(OH)2 \(\underrightarrow{\left(2\right)}\) MgCl2\(\underrightarrow{\left(3\right)}\) KCl \(\underrightarrow{\left(4\right)}\) KNO3
B/ \(Na\underrightarrow{\left(1\right)}Na_2O\underrightarrow{\left(2\right)}NaOH\underrightarrow{\left(3\right)}Na_2SO_4\underrightarrow{\left(4\right)}NaCl\underrightarrow{\left(5\right)}NaNO_3\underrightarrow{\left(6\right)}NaCl\underrightarrow{\left(7\right)}NaOH\)
C/\(Mg\underrightarrow{\left(1\right)}MgO\underrightarrow{\left(2\right)}MgCl_2\underrightarrow{\left(3\right)}Mg\left(NO_3\right)_2\underrightarrow{\left(4\right)}Mg\left(OH\right)_2\underrightarrow{\left(5\right)}MgSO_4\underrightarrow{\left(6\right)}MgCO_3\)
D/\(CuSO_4\underrightarrow{\left(1\right)}Cu\left(OH\right)_2\underrightarrow{\left(2\right)}CuO\underrightarrow{\left(3\right)}CuCl_2\underrightarrow{\left(4\right)}Cu\left(OH\right)_2\underrightarrow{\left(5\right)}CuSO_4\)
E/\(CuCl_2\underrightarrow{\left(1\right)}Cu\left(OH\right)_2\underrightarrow{\left(2\right)}CuSO_4\underrightarrow{\left(3\right)}Cu\underrightarrow{\left(4\right)}CuO\)
F/ \(Cu\left(OH\right)_2\underrightarrow{\left(1\right)}CuO\underrightarrow{\left(2\right)}CuCl_2\underrightarrow{\left(3\right)}Cu\left(NO_3\right)_2\underrightarrow{\left(4\right)}NaNO_3\)
G/\(Fe_2O_3\underrightarrow{\left(1\right)}FeCl_3\underrightarrow{\left(2\right)}Fe\left(OH\right)_3\underrightarrow{\left(3\right)}Fe_2O_3\underrightarrow{\left(4\right)}Fe_2\left(SO_4\right)_3\)
H/ \(ZnCl_2\underrightarrow{\left(1\right)}Zn\left(OH\right)_2\underrightarrow{\left(2\right)}ZnCl_2\underrightarrow{\left(3\right)}NaCl\underrightarrow{\left(4\right)}NaNO_3\)
M/\(CuO\underrightarrow{\left(1\right)}CuCl_2\underrightarrow{\left(2\right)}Cu\left(OH\right)_2\underrightarrow{\left(3\right)}CuO\underrightarrow{\left(4\right)}CuSO_4\)
N/\(Fe\left(OH\right)_2\underrightarrow{\left(1\right)}FeO\underrightarrow{\left(2\right)}FeCl_2\underrightarrow{\left(3\right)}Fe\left(ỌH_2\right)\underrightarrow{\left(4\right)}FeSO_4\underrightarrow{\left(5\right)}FeCl_2\underrightarrow{\left(6\right)}Fe\left(NO_3\right)_2\)
Z/ \(Mg\left(OH\right)_2\underrightarrow{\left(1\right)}MgO\underrightarrow{\left(2\right)}MgSO_4\underrightarrow{\left(3\right)}MgCl_2\underrightarrow{\left(4\right)}Mg\left(OH\right)_2\underrightarrow{\left(5\right)}MgCl_2\underrightarrow{\left(6\right)}Mg\left(NO_3\right)_2\)
X/\(Al\left(OH\right)_3\underrightarrow{\left(1\right)}Al_2O_3\underrightarrow{\left(2\right)}AlCl_3\underrightarrow{\left(3\right)}Al\underrightarrow{\left(4\right)}Al_2\left(SO_4\right)_3\)
g) 1. Fe2O3 + 6HCl → 2FeCl3 + 3H2O
2. FeCl3 + 3NaOH → 3NaCl + Fe(OH)3↓
3. 2Fe(OH)3 \(\underrightarrow{to}\) Fe2O3 + 3H2O
4. Fe2O3 + 3H2SO4 → Fe2(SO4)3 + 3H2O
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h) 1. ZnCl2 + 2NaOH → 2NaCl + Zn(OH)2↓
2. Zn(OH)2 + 2HCl → ZnCl2 + 2H2O
3. ZnCl2 + 2NaOH → 2NaCl + Zn(OH)2↓
4. NaCl + AgNO3 → NaNO3 + AgCl↓
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m) 1. CuO + 2HCl → CuCl2 + H2O
2. CuCl2 + 2NaOH → 2NaCl + Cu(OH)2↓
3. Cu(OH)2 \(\underrightarrow{to}\) CuO + H2O
4. CuO + H2SO4 → CuSO4 + H2O
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11 tháng 5 2021 lúc 16:45
\(\left[\dfrac{\left(x-1\right)\left(x+1\right)}{\left(x-1\right)\left(x+1\right)^2}\right]:\left[\dfrac{\left(x+2\right)\left(x+1\right)-2}{\left(x-1\right)\left(x+1\right)\left(x+2\right)}\right]\)
Tính tiếp hộ mình với
Lời giải:
Đặt biểu thức trên là $A$ thì:
\(A=\frac{1}{x+1}:\frac{x^2+3x+2-2}{(x-1)(x+1)(x+2)}=\frac{1}{x+1}:\frac{x(x+3)}{(x-1)(x+1)(x+2)}\)
\(=\frac{1}{x+1}.\frac{(x-1)(x+1)(x+2)}{x(x+3)}=\frac{(x-1)(x+2)}{x(x+3)}\)
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Giải các hệ phương trình :a) left{{}begin{matrix}left(x-3right)left(2y+5right)left(2x+7right)left(y-1right)left(4x+1right)left(3y-6right)left(6x-1right)left(2y+3right)end{matrix}right.;b) left{{}begin{matrix}left(x+yright)left(x-1right)left(x-yright)left(x+1right)left(2xyright)left(y-xright)left(y+1right)left(y+xright)left(y-2right)-2xyend{matrix}right..
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Giải các hệ phương trình :
a) \(\left\{{}\begin{matrix}\left(x-3\right)\left(2y+5\right)=\left(2x+7\right)\left(y-1\right)\\\left(4x+1\right)\left(3y-6\right)=\left(6x-1\right)\left(2y+3\right)\end{matrix}\right.\);
b) \(\left\{{}\begin{matrix}\left(x+y\right)\left(x-1\right)=\left(x-y\right)\left(x+1\right)\left(2xy\right)\\\left(y-x\right)\left(y+1\right)=\left(y+x\right)\left(y-2\right)-2xy\end{matrix}\right.\).
1) Alxrightarrow[]{left(1right)}Al_2O_3xrightarrow[]{left(2right)}AlCl_3xrightarrow[]{left(3right)}Alleft(OHright)_3
2) Alxrightarrow[]{left(1right)}AlCl_3xrightarrow[]{left(2right)}Alleft(OHright)_3xrightarrow[]{left(3right)}Al_2O_3
3) Fexrightarrow[]{left(1right)}FeSO_4xrightarrow[]{left(2right)}FeCl_2xrightarrow[]{left(3right)}Feleft(OHright)_2xrightarrow[]{left(4right)}FeO
4) Feleft(OHright)_2xrightarrow[]{left(1right)}FeOxrightarrow[]{left(2right)}FeSO_4xrightarrow[]{left(3right)}FeCl_2x...
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1) \(Al\xrightarrow[]{\left(1\right)}Al_2O_3\xrightarrow[]{\left(2\right)}AlCl_3\xrightarrow[]{\left(3\right)}Al\left(OH\right)_3\)
2) \(Al\xrightarrow[]{\left(1\right)}AlCl_3\xrightarrow[]{\left(2\right)}Al\left(OH\right)_3\xrightarrow[]{\left(3\right)}Al_2O_3\)
3) \(Fe\xrightarrow[]{\left(1\right)}FeSO_4\xrightarrow[]{\left(2\right)}FeCl_2\xrightarrow[]{\left(3\right)}Fe\left(OH\right)_2\xrightarrow[]{\left(4\right)}FeO\)
4) \(Fe\left(OH\right)_2\xrightarrow[]{\left(1\right)}FeO\xrightarrow[]{\left(2\right)}FeSO_4\xrightarrow[]{\left(3\right)}FeCl_2\xrightarrow[]{\left(4\right)}Fe\left(OH\right)_2\)
5) \(Fe\xrightarrow[]{\left(1\right)}FeCl_2\xrightarrow[]{\left(2\right)}Fe\left(NO_3\right)_2\xrightarrow[]{\left(3\right)}Fe\left(OH\right)_2\xrightarrow[]{\left(4\right)}FeSO_4\)
6) \(Fe\xrightarrow[]{\left(1\right)}FeCl_3\xrightarrow[]{\left(2\right)}Fe\left(OH\right)_3\xrightarrow[]{\left(3\right)}Fe_2\left(SO_4\right)_3\xrightarrow[]{\left(4\right)}FeCl_3\)
7) \(Fe\left(NO_3\right)_3\xrightarrow[]{\left(1\right)}Fe\left(OH\right)_3\xrightarrow[]{\left(2\right)}Fe_2O_3\xrightarrow[]{\left(3\right)}Fe\xrightarrow[]{\left(4\right)}FeCl_3\)
8) \(Fe_2\left(SO_4\right)_3\xrightarrow[]{\left(1\right)}Fe\left(OH\right)_3\xrightarrow[]{\left(2\right)}Fe_2O_3\xrightarrow[]{\left(3\right)}Fe_2\left(SO_4\right)_3\xrightarrow[]{\left(4\right)}FeCl_3\)
1
1)4 Al+3O2→2Al2O3
(2)Al2O3+6HCl→2AlCl3+3H2O
(3)AlCl3+3NaOH→Al(OH)3+3NaCl
2
4Al+3O2→2Al2O3
Al2O3+6HCl→2AlCl3+3H2O
AlCl3+3NaOH→Al(OH)3+3NaCl
3
Fe+H2SO4→FeSO4+H2
(2)FeSO4+BaCl2→FeCl2+BaSO4
(3)FeCl2+2NaOH→Fe(OH)2+2NaCl
(4)Fe(OH)2→FeO+H2O
4
Fe+H2SO4→FeSO4+H2
FeSO4+BaCl2→FeCl2+BaSO4
FeCl2+2NaOH→Fe(OH)2+2NaCl
Fe(OH)2→FeO+H2O
5
Fe+2HCl→FeCl2+H2
(2)FeCl2+2AgNO3→Fe(NO3)2+2AgCl
(3)Fe(NO3)2+2NaOH→Fe(OH)2+2NaNO3
(4)Fe(OH)2+MgSO4→FeSO4+Mg(OH)2
Câu 1 :
( 1 ) 4Al + 3O2 → 2Al2O3 ( Nhiệt độ )
( 2 ) Al2O3 + 6HCl → 2AlCl3 + 3H2O
( 3 ) AlCl3 + 3NaOH → Al(OH)3 + 3NaCl
Câu 2 :
( 1 ) 2Al + 6HCl → 2AlCl3 + 3H2
( 2 ) AlCl3 + 3NaOH → Al(OH)3 + 3NaCl
( 3 ) 2Al(OH)3 → Al2O3 + 3H2O ( Nhiệt độ )
Câu 3 :
( 1 ) Fe + H2SO4 → H2 + FeSO4
( 2 ) BaCl2 + FeSO4 → FeCl2 + BaSO4
( 3 ) FeCl2 + 2NaOH → NaCl + Fe(OH)2
( 4 ) Fe(OH)2 → FeO + H2O ( Nhiệt độ )
Câu 4 :
( 1 ) Fe(OH)2 → FeO + H2O ( Nhiệt độ )
( 2 ) FeO + H2SO4 → H2O + FeSO4
( 3 ) BaCl2 + FeSO4 → FeCl2 + BaSO4
( 4 ) FeCl2 + 2NaOH → NaCl + Fe(OH)2
Câu 5 :
( 1 ) Fe + 2HCl → FeCl2 + H2
( 2 ) 2AgNO3 + FeCl2 → 2AgCl + Fe(NO3)2
( 3 ) Fe(NO3)2 + NaOH → NaNO3 + Fe(OH)2
( 4 ) H2SO4 + Fe(OH)2 → 2H2O + FeSO4
Câu 6 :
( 1 ) 3Cl2 + 2Fe → 2FeCl3 ( Nhiệt độ )
( 2 ) 3NaOH + FeCl3 → 3NaCl + Fe(OH)3
( 3 ) 3H2SO4 + 2Fe(OH)3 → Fe2(SO4)3 + 6H2O
( 4 ) 3BaCl2 + Fe2(SO4)3 → 2FeCl3 + 3BaSO4
Câu 7 :
( 1 ) 3NaOH + Fe(NO3)3 → 3NaNO3 + Fe(OH)3
( 2 ) 2Fe(OH)3 → Fe2O3 + 3H2O ( Nhiệt độ )
( 3 ) 2Al + Fe2O3 → Al2O3 + 2Fe
( 4 ) 3Cl2 + 2Fe → 2FeCl3 ( Nhiệt độ )
Câu 8 :
( 1 ) Fe2(SO4)3 + 6NaOH → 3Na2SO4 + 2Fe(OH)3
( 2 ) 2Fe(OH)3 → Fe2O3 + 3H2O ( Nhiệt độ )
( 3 ) Fe2O3 + 3H2SO4 → Fe2(SO4)3 + 3H2O
( 4 ) 3BaCl2 + Fe2(SO4)3 → 2FeCl3 + 3BaSO4
\(\dfrac{\left(x+1\right)\left(x+2\right)-\left[\left(x+1\right)-x\right]}{\left(x+2\right)\left[\left(x+1\right)^2-x\right]}-\dfrac{\left(x+1\right)+2-\left(x+1\right)\left[\left(x+1\right)^3+1\right]}{\left(x+1\right)^3+1}\)