6 + 4 = 210
9 + 2 = 711
8 + 5 = 313
5 + 2 = 37
\(\Rightarrow\) 7+ 6 =???
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1) \(4FeS_2+11O_2\rightarrow8SO_2+2Fe_2O_3\)
2) \(2SO_2+O_2\rightarrow2SO_3\)
3) \(SO_3+H_2O\rightarrow H_2SO_4\)
4) \(H_2SO_4+K_2SO_3\rightarrow K_2SO_4+H_2O+SO_2\uparrow\)
5) \(SO_2+Na_2O\rightarrow Na_2SO_3\)
6) \(Na_2SO_3+BaS\rightarrow Na_2S+BaSO_3\downarrow\)
7) \(BaSO_3\rightarrow BaO+SO_2\uparrow\)
8) \(SO_2+Ba\left(OH\right)_2\rightarrow BaSO_3+H_2O\)
9) \(H_2SO_4+Na_2SO_3\rightarrow Na_2SO_4+SO_2+H_2O\)
10) \(Na_2SO_4+BaCl_2\rightarrow2NaCl+BaSO_4\)
\(1,CH_4+Cl_2\underrightarrow{\text{ánh sáng}}CH_3Cl\\ 2,C_6H_6+Br_2\xrightarrow[t^o]{Fe}C_6H_5Br\\ 3,C_6H_6+Cl_2\underrightarrow{\text{ánh sáng}}C_6H_5Cl\\ 4,2CH_3COOH+CaCO_3\rightarrow\left(CH_3COO\right)_2Ca+CO_2\uparrow+H_2O\\ 5,\left(RCOO\right)_3C_3H_5+3NaOH\rightarrow3RCOONa+C_3H_5\left(OH\right)_3\\ 6,CaCO_3+CO_2+H_2O\rightarrow Ca\left(HCO_3\right)_2\\ 7,2NaHCO_3\underrightarrow{t^o}Na_2CO_3+CO_2\uparrow+H_2O\\ 8,NaOH+SiO_2\underrightarrow{t^o}Na_2SiO_3+H_2O\)
\(9,NaHCO_3+HCl\rightarrow NaCl+CO_2\uparrow+H_2O\\ 10,Cl_2+H_2O⇌HCl+HClO\\ 11,CH_3COOC_2H_5+NaOH\rightarrow CH_3COONa+C_2H_5OH\\ 12,C_6H_6+3H_2\xrightarrow[t^o]{Ni}C_6H_{12}\\ 13,\left(RCOO\right)_3C_3H_5+3H_2O\rightarrow3RCOOH+C_3H_5\left(OH\right)_3\\ 14,\left(-C_6H_{10}O_5-\right)_n+nH_2O\rightarrow nC_6H_{12}O_6\\ 15,CH_3COONa+NaOH\underrightarrow{t^o}CH_4\uparrow+Na_2CO_3\\16, Ca\left(HCO_3\right)\underrightarrow{t^o}CaCO_3+CO_2\uparrow+H_2O\)
\(17,MnO_2+4HCl\rightarrow MnCl_2+Cl_2\uparrow+2H_2O\\ 18,NaHCO_3+NaOH\rightarrow Na_2CO_3+H_2O\\ 19,2C_4H_{10}+5O_2\xrightarrow[men,xt]{t^o}4CH_3COOH+2H_2O\\ 20,2NaOH+Cl_2\rightarrow NaCl+NaClO+H_2O\\ 21,CH_3COOC_2H_5+H_2O\underrightarrow{t^o}CH_3COOH+C_2H_5OH\)
Lời giải:\(\lim\limits_{x\to -\infty}\frac{(2-x^4)(3x^5-1)}{7+9x-x^6}=\lim\limits_{x\to -\infty}\frac{(\frac{2}{x}-x^3)(3-\frac{1}{x^5})}{\frac{7}{x^6}+\frac{9}{x^5}-1}\)
Ta thấy:
\(\lim\limits_{x\to -\infty}(\frac{2}{x}-x^3)=+\infty \)
\(\lim\limits_{x\to -\infty}\frac{3-\frac{1}{x^5}}{\frac{7}{x^6}+\frac{9}{x^5}-1}=\frac{3}{-1}=-3<0\)
\(\Rightarrow \lim\limits_{x\to -\infty}\frac{(2-x^4)(3x^5-1)}{7+9x-x^6}=-\infty \)
\(\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\left(\dfrac{1}{12}+\dfrac{2}{4}\right)\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\left(\dfrac{1}{12}+\dfrac{6}{12}\right)\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{3}{5}\right)-\dfrac{7}{12}\right]\\ =\dfrac{3}{4}-\left[\left(-\dfrac{36}{60}\right)-\dfrac{35}{60}\right]\\ =\dfrac{3}{4}-\left(-\dfrac{71}{60}\right)\\ =\dfrac{3}{4}+\dfrac{71}{60}\\ =\dfrac{35}{60}+\dfrac{71}{60}\\ =\dfrac{106}{60}\\ =\dfrac{53}{30}\)
__
\(-\dfrac{6}{7}.\dfrac{21}{12}\\ =-\dfrac{126}{84}\\ =-\dfrac{63}{42}\\ =-\dfrac{31}{14}\)
__
\(\left(-5\right).\left(-\dfrac{6}{20}\right)\\ =\dfrac{\left(-5\right).\left(-6\right)}{20}\\ =\dfrac{30}{20}\\ =\dfrac{3}{2}\)
__________
Bài 2:
a: 2/6x5/3=10/18=5/9
b: 11/9x5/10=55/90=11/18
c: 3/9x6/8=1/3x3/4=1/4
d: 4/9x12/16=48/144=1/3
e: 25/15x6/7=5/3x6/7=30/21=10/7
f: 6/10x15/20=90/200=9/20
Bài 1
4/5 x 6/7= 24/35
2/9 x 1/2= 2/18= 1/9
1/2 x 8/3= 8/6= 4/3
7/9 x 6/5= 42/45= 14/15
8/7 x 5/9= 40/63
10/11 x 22/15= 220/165= 4/3
Bài 2
2/6 x 5/3= 1/3 x 5/3=5/9
11/9 x 5/10= 11/9 x 1/2= 11/18
3/9 x 6/8= 1/3 x 3/4 =3/12= 1/4
4/9 x 12/16= 4/9 x 3/4= 12/36= 1/3
25/15 x 6/7= 5/3 x 6/7= 30/21= 10/7
6/10 x 15/20= 3/5 x 3/4= 9/20
7+6=113
chac chan luon
Quy luật :
6+4=10
6-4=2
Nên ta có: 6+4=210
theo quy luật trên 7+6=113