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\(4.3^{x-1}+2.3^{x+2}=4.3^6+2.3^9\)
\(3^{x-1}.\left(4+2.3^3\right)=3^6.\left(4+2.3^3\right)\)
\(\Leftrightarrow3^{x-1}=3^6\)
\(\Leftrightarrow x-1=6\)
\(\Leftrightarrow x=7\)
Vậy \(x=7\)
1: x=3/4-1/2=3/4-2/4=1/4
2: x-1/5=2/11
=>x=2/11+1/5=21/55
3: x-5/6=16/42-8/56
=>x-5/6=8/21-4/28=5/21
=>x=5/21+5/6=15/14
4: x/5=5/6-19/30
=>x/5=25/30-19/30=6/30=1/5
=>x=1
5: =>|x|=1/3+1/4=7/12
=>x=7/12 hoặc x=-7/12
6: x=-1/2+3/4
=>x=3/4-1/2=1/4
11: x-(-6/12)=9/48
=>x+1/2=3/16
=>x=3/16-1/2=-5/16
1)x= 1/4
2)x= 2/11+ 1/5
x= 21/55
3)x - 5/6 = 5/21
x = 5/21+5/6
x = 15/14
4)x/5 = 5/6 + -19/30
x:5 = 1/5
x = 1/5.5
x = 1
5) |x| - 1/4 = 6/18
|x| = 6/18 - 1/4
|x| =7/12
⇒x= 7/12 hoặc -7/12
6)x = -1/2 +3/4
x= 1/4
7) x/15 = 3/5 + -2/3
x:15 = -1/15
x = -1/15. 15
x = -1
8)11/8 + 13/6 = 85/x
85/24 = 85/x
⇒ x = 24
9) x - 7/8 = 13/12
x = 13/12 + 7/8
x = 47/24
10)x - -6/15 = 4/27
x = 4/27 + (-6/15)
x = -34/135
11) -(-6/12)+x = 9/48
x= 9/48 - 6/12
x = -5/16
12) x - 4/6 = 5/25 + -7/15
x -4/6 = -4/15
x = -4/15 + 4/6
x = 2/5
\(\left(-\dfrac{3}{7}\right)\times\dfrac{5}{11}+\left(-\dfrac{3}{7}\right)\times\dfrac{6}{11}+2\times\dfrac{3}{7}\)
\(=\left(-\dfrac{3}{7}\right)\times\left(\dfrac{5}{11}+\dfrac{6}{11}-2\right)\)
\(=\left(-\dfrac{3}{7}\right)\times\left(1-2\right)\)
\(=\left(-\dfrac{3}{7}\right)\times\left(-1\right)\)
\(=\dfrac{3}{7}\)
Lời giải:
1.
$3^{x+2}+4.3^{x+1}=7.3^6$
$3^{x+1}.3+4.3^{x+1}=7.3^6$
$3^{x+1}(3+4)=7.3^6$
$3^{x+1}.7=7.3^6$
$\Rightarrow 3^{x+1}=3^6$
$\Rightarrow x+1=6$
$\Rightarrow x=5$
2.
$5^{x+4}-3.5^{x+3}=2.5^{11}$
$5^{x+3}.5-3.5^{x+3}=2.5^{11}$
$5^{x+3}(5-3)=2.5^{11}$
$2.5^{x+3}=2.5^{11}$
$\Rightarrow 5^{x+3}=5^{11}$
$\Rightarrow x+3=11$
$\Rightarrow x=8$
3.
$4^{x+3}-3.4^{x+1}=13.4^{11}$
$4^{x+1}.4^2-3.4^{x+1}=13.4^{11}$
$4^{x+1}.16-3.4^{x+1}=13.4^{11}$
$13.4^{x+1}=13.4^{11}$
$\Rightarrow 4^{x+1}=4^{11}$
$\Rightarrow x+1=11$
$\Rightarrow x=10$
a)-5x.5x+4.5x+3+(-4)-3=2.511
5x+6.511-2=4+3
5x+17=7-2
5x+17=51
=>x+17=1
=>x=-16
mk bt câu a thôi
b: \(\Leftrightarrow5^x\cdot75+5^x\cdot\dfrac{4}{125}=19\cdot5^{10}\)
\(\Leftrightarrow5^x\simeq24729\)
hay \(x\in\varnothing\)
c: \(\Leftrightarrow2^x\cdot\left(5+3\cdot4\right)=6^{11}\left(11+2\cdot36\right)\)
=>2^x=1771303273
hay \(x\in\varnothing\)
b) Ta có: \(5^{x+4}-3\cdot5^{x+3}=2\cdot5^{11}\)
\(\Leftrightarrow2\cdot5^{x+3}=2\cdot5^{11}\)
\(\Leftrightarrow x+3=11\)
hay x=8
c) Ta có: \(2\cdot3^{x+2}+4\cdot3^{x+1}=10\cdot3^6\)
\(\Leftrightarrow18\cdot3^x+12\cdot3^x=10\cdot3^6\)
\(\Leftrightarrow30\cdot3^x=30\cdot3^5\)
Suy ra: x=5
d) Ta có: \(6\cdot8^{x-1}+8^{x+1}=6\cdot8^{19}+8^{21}\)
\(\Leftrightarrow6\cdot\dfrac{8^x}{8}+8^x\cdot8=6\cdot8^{19}+64\cdot8^{19}\)
\(\Leftrightarrow8^x\cdot\dfrac{35}{4}=70\cdot8^{19}\)
\(\Leftrightarrow8^x=8^{20}\)
Suy ra: x=20
\(-\dfrac{3}{4}.\dfrac{4}{11}+\left(-\dfrac{5}{4}\right).\dfrac{4}{11}=\dfrac{4}{11}\left(-\dfrac{3}{4}-\dfrac{4}{4}\right)=\dfrac{4}{11}.\left(-\dfrac{4}{7}\right)=-\dfrac{16}{77}\)
\(\dfrac{7}{12}-\left(-\dfrac{1}{5}\right)-\dfrac{5}{6}+\dfrac{2}{3}+\left(-\dfrac{1}{5}\right)\)
\(=\dfrac{7}{12}+\dfrac{1}{5}-\dfrac{5}{6}+\dfrac{2}{3}-\dfrac{1}{5}\)
\(=\dfrac{7}{12}-\dfrac{5}{6}+\dfrac{2}{3}=\dfrac{7}{12}-\dfrac{10}{12}+\dfrac{8}{12}=\dfrac{5}{12}\)