a) 52x-3 - 2.52= 52.3
b) 64.4n = 45
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b) 32x = 81
32x = 34
=> 2x = 4
=> x = 2
a). 52x-3 – 2.52 = 52 .3
52x: 53 = 52 .3 + 2.52
52x: 53 = 52 .5
52x = 52 .5.53
52x = 56
=> 2x = 6
=> x=3
52x-3-2.52 =52 . 3
⇔52x-1.52-2.52=52.3
⇔52.(52x-1-2)=52.3
⇔52x-1-2=3
⇔52x-1=5
⇔2x-1=1
⇔2x=2
⇔x=1
vay x=1
\(\Rightarrow5^{2x-3}=5^2\cdot3+5^2\cdot2=5^2\cdot5=5^3\\ \Rightarrow2x-3=3\\ \Rightarrow x=3\)
\(5^{2x-3}-2.5^2=5^2.3\)
\(\Rightarrow5^{2x-3}-50=75\)
\(\Rightarrow5^{2x-3}=125=5^3\)
\(\Rightarrow2x-3=3\Rightarrow2x=6\Rightarrow x=3\)
5²ˣ⁻³ - 2.5² = 5².3
5²ˣ⁻³ - 2.25 = 25.3
5²ˣ⁻³ - 50 = 75
5²ˣ⁻³ = 75 + 50
5²ˣ⁻³ = 125
5²ˣ⁻³ =5³
2x - 3 = 3
2x = 3 + 3
2x = 6
x = 6 : 2
x = 3
\(5^{2x-3}-2.5^2=5^2.3\)
\(\Leftrightarrow5^{2x}:5^3-50=75\)
\(\Leftrightarrow5^{2x}:5^3=75+50\)
\(\Leftrightarrow5^{2x}:5^3=125\)
\(\Leftrightarrow5^{2x}=125.5^3\)
\(\Leftrightarrow5^{2x}=5^3.5^3\)
\(\Leftrightarrow5^{2x}=5^6\)
\(\Leftrightarrow2x=6\)
\(\Leftrightarrow x=6:2\)
\(\Leftrightarrow x=3\)
Vậy x=3
a). 5x = 125
=>5x = 53
=> x = 3
b) 32x = 81
=> 32x = 34
=> 2x = 4
=> x = 2
c). 52x-3 – 2.52 = 52 .3
=>52x: 53 = 52 .3 + 2.52
=>52x: 53 = 52 .5
=>52x = 52 .5.53
=>52x = 56
=> 2x = 6
=> x=3
a) 5x = 125
x = 125 : 5
x = 25
b) 32x = 81
x = 81 : 32
x = 81/ 32
c) 52x - 3 - 2.52 = 52.3
52x - 3 - 104 = 156
x - 3 - 104 = 156 : 52
x - 3 - 104 = 3
x - 3 = 3 + 104
x - 3 = 107
x = 107 + 3
x = 110
Ko chắc lắm , sai thì Sorry nhé .
a, 2.(x – 5)+7 = 77
<=> 2.(x – 5) = 70 <=> x – 5 = 35 <=> x = 40
b, x - 1 3 - 3 5 : 3 4 + 2 . 2 3 = 14
<=> x - 1 3 - 3 + 2 4 = 14
<=> x - 1 3 = 14 + 3 - 16 = 1
<=> x – 1 = 1 <=> x = 2
c, 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1
Đặt: A = 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 => 2A = 2 + 2 2 + 2 3 + . . . + 2 2017
=> 2A – A = ( 2 + 2 2 + 2 3 + . . . + 2 2017 ) – ( 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 )
=> A = 2 2017 - 1
Ta có: 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1 => 2 2017 - 1 = 2 x - 1 - 1 => x = 2018
d, 5 2 x - 3 - 2 . 5 2 = 5 2 . 3
<=> 5 2 x - 3 = 5 2 . 3 + 5 2 . 2
<=> 5 2 x - 3 = 5 2 . ( 3 + 2 )
<=> 5 2 x - 3 = 5 3
<=> 2x – 3 = 3 => x = 3
Lời giải:
a.
$5^{2x-3}-2.5^2=5^2.3$
$5^{2x-3}=2.5^2+5^2.3=5^2(2+3)=5^2.5=5^3$
$\Rightarrow 2x-3=3$
$\Rightarrow 2x=6\Rightarrow x=3$
b.
$64.4^n=4^5$
$4^3.4^n=4^5$
$4^{n+3}=4^5$
$n+3=5$
$n=5-3$
$n=2$