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(4x+2^2)=2.6^2016:6^2015
4x+4=2.6^1
4x+4=12
4x=12-4
4x=8
x=2
k cho mình nha.Chúc bạn học tốt
(4x+22).62015=2.62016
=>(4x+22)=2.62016:62015
=>4x+4=2.6
=>4x+4=12
=>4x=12-4
=>4x=8
=>x=8:2
=>x=2
Vậy x=2
Lời giải:
$\frac{7}{10^{2015}}+\frac{15}{10^{2016}}-(\frac{7}{10^{2016}}+\frac{15}{10^{2015}})$
$=\frac{-8}{10^{2015}}+\frac{8}{10^{2016}}=8(\frac{1}{10^{2016}}-\frac{1}{10^{2015}})<0$
$\Rightarrow \frac{7}{10^{2015}}+\frac{15}{10^{2016}}< \frac{7}{10^{2016}}+\frac{15}{10^{2015}}$
a ) \(x^2-5=11\)
\(\Leftrightarrow x^2=11+5\)
\(\Leftrightarrow x^2=16\)
\(\Leftrightarrow x=\pm\sqrt{16}\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=4\\x=-4\end{array}\right.\)
Vậy \(x\in\left\{4;-4\right\}\)
b ) \(4x^3+15=19\)
\(\Leftrightarrow4x^3=19-15\)
\(\Leftrightarrow4x^3=4\)
\(\Leftrightarrow x^3=4:4\)
\(\Leftrightarrow x^3=1\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
a)4x3+15=47
4x3=47-15
4x3=32
x3=32:4
x3=8
x3=23
vậy x = 2
b)4.2x-3=125
4.2x=125+3
4.2x=128
2x=128:4
2x=32
2x=25
Vậy x=5
a) 4x3 + 15 = 47 b) 4.2x - 3 = 125
4x3 = 47 - 15 4.2x = 125 + 3
4x3 = 32 4.2x = 128
x3 = 32 : 4 2x = 128 : 4
x3 = 8 2x = 32
x3 = 23 2x = 25
=> x = 2 => x = 5
Ta có:
x biết: 2016 x 2016 - 2015 x 2017 + x = 2016
x = 2015 x 2017 + 2016 - 2016 x 2016
x = 2015 x 2017 + 2016 x (1 - 2016)
x = 2015 x 2017 - 2015 x 2016
x = 2015 x (2017 - 2016)
x = 2015 x 1
x = 2015
| x + 3 | + 3x = 15
=> |x+3|=15-3x
TH1 : x+3=-(15-3x)
=> x+3 = -15+3x
=> x= -15+3x-3
=> x= (-15-3 )+3x
=> x = -18+3x
=> 0= -18+(3x-x)
=> 0=-18+2x
=> 2x = 18
=> x = 9
17x - 4x = 88:86+(2016)0
<=> 82 + 1 = 13x
<=> 65 = 13x
<=> x = 5
\(17x-4x=8^8:8^6+\left(2016\right)^0\)
\(\Rightarrow13x=8^2+1\)
\(\Rightarrow13x=65\)
\(\Rightarrow x=5\)
Vậy \(x=5\)
\(\left(4x-15\right)^{2016}=\left(4x-15\right)^{2015}\\ \Leftrightarrow\left[{}\begin{matrix}4x-15=0\\4x-15=1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}4x=15\\4x=16\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{15}{4}\\x=4\end{matrix}\right.\)
Vậy \(x\in\left\{\dfrac{15}{4};4\right\}\)