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NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
23 tháng 7 2023
a, 27.\(3^x\) = 243
\(3^x\) = 243 : 27
\(3^x\) = 9
\(3^x\) = 32
\(x\) = 2
b, 49.7\(^x\) = 2041
7\(^x\) = 2041: 49
7\(^x\) = 41,65
\(x\) = log741,56
\(x\) ≈ 1,916
c, 64.4\(^x\) = 4\(^5\)
4\(^x\) = 45 : 64
4\(^x\) = 4
\(x\) = 1
d, 3\(^x\) = 243
3\(^x\) = 35
\(x\) = 5
e, 2\(^{x+5}\) = 128
\(2^{x+5}\) = 27
\(x+5\) = 7
\(x\) = 7 - 5
\(x\) = 2
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
23 tháng 7 2023
f, 3.3\(^x\) = 81
3\(^x\) = 81 : 3
3\(^x\) = 27
3\(^x\) = 33
\(x\) = 3
g, 25 + 5\(^x\).5\(^x\) = 650
5\(^{2x}\) = 650 - 25
5\(^{2x}\) = 625
5\(^{2x}\) = 54
2\(x\) = 4
\(x\) = 2
19 tháng 8 2023
a: Kẻ Ox//AB
Ox//AB
=>góc xOA=góc OAB(hai góc so le trong)
=>góc xOA=41 độ
góc xOA+góc xOB=góc AOB
=>góc xOB=71-41=30 độ=góc OCD
=>Ox//CD
=>AB//CD
=>Ax//Cy
b: BD//AO
=>góc B+góc OAB=180 độ(trong cùng phía)
=>góc B=180-41=139 độ
AB//CD
=>góc B+góc D=180 độ(hai góc trong cùng phía)
=>góc D=180-139=41 độ
KY
18 tháng 12 2021
better not eat too much junk food
been reading that book for 2 weeks
When I arrived last night, he was watching TV
going to bed late last night, she felt tired
AD
23 tháng 7 2023
\(a,27.3^x=243\\ \Rightarrow3^x=243:27\\ \Rightarrow3^x=9\\ \Rightarrow3^x=3^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(b,49.7^x=2041\\ \Rightarrow7^x=2041:49\\ \Rightarrow7^x=7^4:7^2\\ \Rightarrow7^x=7^{4-2}\\ \Rightarrow7^x=7^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(c,64.4^x=4^5\\ \Rightarrow4^x=4^5:4^3\\ \Rightarrow4^x=4^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(d,3^x=243\\ \Rightarrow3^x=3^5\\ \Rightarrow x=5\left(thoaman\right)\)
\(e,2^{x+5}=128\\ \Rightarrow2^x.2^5=2^7\\ \Rightarrow2^x=2^7:2^5\\ \Rightarrow2^x=2^2\\ \Rightarrow x=2\left(thoaman\right)\)
\(f,3.3^x=81\\ \Rightarrow3^x=81:3\\ \Rightarrow3^x=27\\ \Rightarrow3^x=3^3\\ \Rightarrow x=3\left(thoaman\right)\)
\(g,25+5^x.5^x=650\\ \Rightarrow5^{2x}=650-25\\ \Rightarrow5^{2x}=625\\ \Rightarrow5^{2x}=5^4\\ \Rightarrow2x=4\\ \Rightarrow x=4:2=2\left(thoaman\right)\)
câu h không rõ đề ?
@seven
\(1.4P+5O_2\overset{t^o}{--->}2P_2O_5\left(4:5:2\right)\)
\(2.2Zn+O_2\overset{t^o}{--->}2ZnO\left(2:1:2\right)\)
\(3.2Fe+3Cl_2\overset{t^o}{--->}2FeCl_3\left(2:3:2\right)\)
\(4.N_2+3H_2\overset{t^o}{--->}2NH_3\left(1:3:2\right)\)
\(5.2Al+3H_2SO_4--->Al_2\left(SO_4\right)_3+3H_2\left(2:3:1:3\right)\)
\(6.P_2O_5+3H_2O--->2H_3PO_4\left(1:3:2\right)\)
\(7.Na_2O+H_2O--->2NaOH\left(1:1:2\right)\)
\(8.Fe_2O_3+6HCl--->2FeCl_3+3H_2O\left(1:6:2:3\right)\)
\(9.2Al\left(OH\right)_3+3H_2SO_4--->Al_2\left(SO_4\right)_3+6H_2O\left(2:3:1:6\right)\)
\(10.MgCl_2+2AgNO_3--->Mg\left(NO_3\right)_2+2AgCl\downarrow\left(1:2:1:2\right)\)
\(11.2FeCl_3+3Ba\left(OH\right)_2--->2Fe\left(OH\right)_3\downarrow+3BaCl_2\left(2:3:2:3\right)\)
\(12.2Al+3CuCl_2--->2AlCl_3+3Cu\downarrow\left(2:3:2:3\right)\)
\(13.2Al+Fe_2O_3\overset{t^o}{--->}2Fe+Al_2O_3\left(2:1:2:1\right)\)
\(14.2Fe\left(OH\right)_3\overset{t^o}{--->}Fe_2O_3+3H_2O\left(2:1:3\right)\)
\(15.2KClO_3\xrightarrow[MnO_2]{t^o}2KCl+3O_2\left(2:2:3\right)\)
\(16.CH_4+2O_2\overset{t^o}{--->}CO_2+2H_2O\left(1:2:1:2\right)\)
\(17.4K+O_2\overset{t^o}{--->}2K_2O\left(4:1:2\right)\)
\(18.2Al+3Cl_2\overset{t^o}{--->}2AlCl_3\left(2:3:2\right)\)
\(19.Mg+2HCl--->MgCl_2+H_2\left(1:2:1:1\right)\)
\(20.3H_2+Fe_2O_3\overset{t^o}{--->}2Fe+3H_2O\left(3:1:2:3\right)\)
\(21.4Na+O_2\overset{t^o}{--->}2Na_2O\left(4:1:2\right)\)
\(22.2Mg+O_2\overset{t^o}{--->}2MgO\left(2:1:2\right)\)
\(23.2Al+6HCl--->2AlCl_3+3H_2\left(2:6:2:3\right)\)
\(24.CuO+2HCl--->CuCl_2+H_2O\left(1:2:1:1\right)\)
\(25.Mg+2AgNO_3--->Mg\left(NO_3\right)_2+2Ag\downarrow\left(1:2:1:2\right)\)
\(26.FeCl_3+3KOH--->3KCl+Fe\left(OH\right)_3\downarrow\left(1:3:3:1\right)\)