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1) 2x . 4 = 128
2x = 128 : 4
2x = 32
2x = 25
=> x = 5
2) (2x + 1)3 = 125
(2x + 1)3 = 53
=> 2x + 1 = 5
2x = 5 - 1
2x = 4
x = 2
các bài khác bạn tự làm nha
\(5x+2x=6^2-5^0\Leftrightarrow5x+2x=6^2-1\)
\(\Leftrightarrow5x-2x=36-1\Leftrightarrow5x-2x=35\Leftrightarrow x\left(5+2\right)=35\)
\(\Leftrightarrow7x=35\Leftrightarrow x=35:7\Leftrightarrow x=5\)
\(5x+x=150:2+3\Leftrightarrow5x+x=75+3\)
\(\Leftrightarrow5x+x=78\Leftrightarrow x\left(5+1\right)=78\Leftrightarrow x6=78\)
\(\Leftrightarrow x=78:6\Leftrightarrow x=13\)
a) 5x + 2x = 62 - 50
7x = 35 => x = 5
b) 5x + x = 150 : 2 + 3
6x = 78 => x = 13
c) 6x + x = 511 : 59 + 31
7x = 28 => x = 4
d) 5x + 3x = 36 : 33 x 4 + 12
8x = 120 => x = 15
e) 4x + 2x = 68 - 219 : 216
6x = 60 => x = 10
f) 5x + x = 39 - 311 : 39
6x = 30 => x = 5
g) 7x - x = 521 : 519 + 3 x 22 - 70
6x = 36 => x = 6
h) 7x - 2x = 617 : 615 + 44 : 11
5x = 40 => x = 8
\(5x+2x=6^2-5^0\)
\(7x=36-1\)
\(7x=35\)
\(x=5\)
vậy \(x=5\)
\(5x+x=150:2+3\)
\(6x=75+3\)
\(x=78:6\)
\(x=13\)
vậy \(x=13\)
những câu sau tương tự
1) 5x + 2x = 6^2 - 5^0
=> 7x = 36 - 1 = 35
=> x = 35 : 5 = 5.
Vậy x = 5
2) 5x + x = 150 : 2 + 3
=> 6x = 75+3 = 78
=> x = 78 : 6 =13.
Vậy x = 13
3) 6x + x = 5^11 : 5^9 - 3^1
=> 7x = 5^2 -3 = 25 - 3 = 22
=> x = 22 : 7 = 22 / 7.
Vậy x = 22/7
4) 5x + 3x = 3^6 : 3^3 .4 + 12
=> 8x = 3^3 .4 + 12= 27.4 + 12 = 108 + 12 =120
=> x = 120 : 8 = 15.
Vậy x = 15
5) 4x + 2x = 68 - 2^19 : 2^16
=> 6x = 68 - 2 ^3 = 68 - 8 =60
=> x = 60 : 6 =10.
Vậy x = 10
6) 5x + x = 39 - 3^11 : 3^9
=> 6x = 39 - 3^2 = 39 - 9 = 30
=> x = 30 : 6 =5.
Vậy x =5
7) 7x - x = 5^21 : 5^19 + 3. 2^2 - 7^0
=> 6x = 5^2 + 3.4 - 1 = 25 + 12 - 1 = 36
=> x = 36 : 6 = 6.
Vậy x = 6
8) 7x - 2x = 6^17 : 6^15 + 44 : 11
=> 5x = 6^2 + 4 = 36 + 4 = 40
=> x = 40 : 5 = 8 .
Vậy x = 8
\(a)5x+x=39-3^{11}\div3^9\)9
\(5x+x1=39-3^2\)
\(5x+x1=39-9\)
\(5x+x1=30\)
\(x\left(1+5\right)=30\)
\(x6=30\)'
\(\Leftrightarrow x=30\div6\)
\(\Leftrightarrow x=5\)
\(b)7x-x=5^{21}\div5^{19}+3.2^2-7^0\)
\(7x-x=5^2+3.4-1\)
\(7x-x1=25+12-1\)
\(7x-x1=37-1\)
\(7x-x1=36\)
\(\Leftrightarrow x\left(7-1\right)=36\)
\(\Leftrightarrow x6=36\)
\(\Leftrightarrow x=36\div6\)
\(\Rightarrow x=6\)
\(c)5x+3x=3^6.4+12\)
\(5x+3x=729.4+12\)
\(5x+3x=2916+12\)
\(5x+3x=2928\)
\(\Leftrightarrow x\left(3+5\right)=2928\)
\(\Leftrightarrow x8=2928\)
\(\Leftrightarrow x=2928\div8\)
\(\Rightarrow x=366\)
\(d)7x-2x=6^{17}\div6^{15}+44\div11\)
\(7x-2x=6^2+44\div11\)
\(7x-2x=36+4\)
\(7x-2x=40\)
\(\Leftrightarrow x\left(7-2\right)=40\)
\(\Leftrightarrow x5=40\)
\(\Leftrightarrow x=40\div5\)
\(\Rightarrow x=8\)
1) \(2^{x+1}\cdot2^{2014}=2^{2015}\)\(\Leftrightarrow2^{2014x+2014}=2^{2015}\)\(\Leftrightarrow2014x+2014=2015\)\(\Leftrightarrow x=\frac{1}{2014}\)
2) \(7x-2x=\frac{6^{17}}{6^{15}}+\frac{44}{11}\)\(\Leftrightarrow5x=6^2+4=36+4=40\)\(\Leftrightarrow x=\frac{40}{5}=8\)
3) \(3^x=9\)\(\Leftrightarrow3^x=3^2\)\(\Leftrightarrow x=2\)
4) \(7x-x=\frac{5^{21}}{5^{19}}+3\cdot2^2-7^0\)\(\Leftrightarrow6x=5^2+3\cdot4-1=25+12-1=36\)\(\Leftrightarrow x=6\)
5) \(4^x=64\)\(\Leftrightarrow4^x=4^3\)\(\Leftrightarrow x=3\)
6) \(9^{x-1}=9\)\(\Leftrightarrow x-1=1\)\(\Leftrightarrow x=0\)
7) \(\frac{2^x}{2^5}=1\)\(\Leftrightarrow2^{x-5}=2^0\)\(\Leftrightarrow x-5=0\)\(\Leftrightarrow x=5\)
8) \(\left(5x-9\right)^3=216\)\(\Leftrightarrow\left(5x-9\right)^3=6^3\)\(\Leftrightarrow5x-9=6\)\(\Leftrightarrow5x=15\)\(\Leftrightarrow x=3\)
9) \(5\cdot3^{7x-11}=135\)\(\Leftrightarrow5.3^{7x-11}=5.3^3\)\(\Leftrightarrow3^{7x-11}=3^3\)\(\Leftrightarrow7x-11=3\)\(\Leftrightarrow7x=14\Leftrightarrow x=2\)
10) \(2.3^x=19\cdot3^8-81^2\)\(\Leftrightarrow2.3^x=19\cdot3^8-3^8=18.3^8=2.3^{11}\)\(\Leftrightarrow3^x=3^{11}\Leftrightarrow x=11\)
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Học tốt ^3^