4^x-1/4^7=64. Hãy tìm x
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a.7,2 :2 x 58,6 + 2,93 x 2 x 64
= 3,6 x 58,6 + 5,86 x 64
=210,96 + 357,04
=586
b.\(4\frac{2}{5}+2\frac{3}{7}-2\frac{2}{5}+5\frac{4}{7}\)
=\(\left(4\frac{2}{5}-2\frac{2}{5}\right)+\left(2\frac{3}{7}+5\frac{4}{7}\right)\)
= 2 + 8
= 10
c. 2 x 41 x 36 + 8 x 9 x 58 + 12 x 6
=72 x 41 + 72 x 58 + 72 x 1
=72 x ( 41 + 58 +1 )
=72 x 100
=7200
d, \(\frac{3}{5}\)x \(\frac{1}{2}\):\(\frac{2}{5}\)
=\(\frac{3}{5}\)x \(\frac{1}{2}\)x\(\frac{5}{2}\)
=\(\frac{3}{4}\)
Ta có : |2x - 1| + 1 = x
=> |2x - 1| = x - 1
\(\Leftrightarrow\orbr{\begin{cases}2x-1=x-1\\2x-1=1-x\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x-x=-1+1\\2x+x=1+1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\3x=2\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\frac{2}{3}\end{cases}}\)
\(x\times\frac{4}{7}+\frac{1}{3}\times x=\frac{2}{3}\)
\(x\times\left(\frac{4}{7}+\frac{1}{3}\right)=\frac{2}{3}\)
\(x\times\frac{19}{21}=\frac{2}{3}\)
\(x=\frac{2}{3}:\frac{19}{21}\)
\(x=\frac{2}{3}\times\frac{21}{19}=\frac{14}{19}\)
\(23\left(x-1\right)+19=65\)
\(23\left(x-1\right)=65-19\)
\(23\left(x-1\right)=46\)
\(x-1=46:23\)
\(x-1=2\)
\(x=2+1\)
\(x=3\)
\(5x+3x=88\)
\(x\left(5+3\right)=88\)
\(x.8=88\)
\(x=88:8\)
\(x=11\)
\(x^3=64\)
\(x^3=4^3\)
\(\Rightarrow x=4\)
\(\left(5x-4\right):7-2=6\)
\(\left(5x-4\right):7=6+2\)
\(\left(5x-4\right):7=8\)
\(5x-4=8.7\)
\(5x-4=56\)
\(5x=56+4\)
\(5x=60\)
\(x=60:5\)
\(x=12\)
\(x^{50}=x\)
\(\Rightarrow x=1\)
\(4.2^x-3=125\)
\(4.2^x=125+3\)
\(4.2^x=128\)
\(2^x=128:4\)
\(2^x=32\)
\(2^x=2^5\)
\(\Rightarrow x=5\)
k mk nha
Từ 1 đến 28 có số số hạng là:
(28 - 1) : 3 + 1 = 10 ( số )
Tươn ứng với nó là 10 số x
Mà tổng của 1 -> 28 là :
(28 + 1 ) x 10 : 2 = 145
Vậy ta có biểu thức :
x x 10 + 145 = 195
x x 10 = 50
x = 50 : 10
x = 5
bài dễ quá .tick cho mình ,mình giải cho nha
a. x + \(\dfrac{3}{7}\)= \(\dfrac{2}{5}:\dfrac{18}{25}=>x+\dfrac{3}{7}=\dfrac{2}{5}\)x\(\dfrac{35}{18}=>x+\dfrac{3}{7}=\dfrac{7}{9}\)
=> x = \(\dfrac{7}{9}-\dfrac{3}{7}=\dfrac{49}{63}-\dfrac{27}{63}=\dfrac{22}{63}\)
b. \(x\) x \(\dfrac{5}{9}\)= \(\dfrac{4}{5}-\dfrac{1}{3}\)
=> \(x\) x \(\dfrac{5}{9}\)= \(\dfrac{12}{15}-\dfrac{5}{15}=>x\) x \(\dfrac{5}{9}\)= \(\dfrac{7}{15}\)
=> x = \(\dfrac{7}{15}:\dfrac{5}{9}\)
=> x = \(\dfrac{21}{25}\)
\(a.x+\dfrac{3}{7}=\dfrac{2}{5}:\dfrac{18}{35}\\x+\dfrac{3}{7}=\dfrac{2}{5}\times\dfrac{35}{18} \\ x+\dfrac{3}{7}=\dfrac{7}{9}\\ x=\dfrac{7}{9}-\dfrac{3}{7}\\ x=\dfrac{22}{63}\)
\(b.x\times\dfrac{5}{9}=\dfrac{4}{5}-\dfrac{1}{3}\\x\times\dfrac{5}{9}=\dfrac{7}{15}\\ x=\dfrac{7}{15}:\dfrac{5}{9}\\ x= \dfrac{21}{25}\)
a)\(-\frac{12}{7}\cdot\left(\frac{3}{4}-x\right)\cdot\frac{1}{4}=0\)
=>\(\frac{3}{4}-x=0\)
=>\(x=\frac{3}{4}\)
Vậy \(x=\frac{3}{4}\)
b) \(x:\frac{17}{8}=-\frac{2}{5}\cdot\left(-\frac{9}{17}\right)\)
=>\(x:\frac{17}{8}=\frac{18}{85}\)
=>\(x=\frac{18}{85}\cdot\frac{17}{8}=\frac{9}{20}\)
Vậy \(x=\frac{9}{20}\)
a, 100 - 7 ( x - 5 ) = 31 + 33
100 - 7 ( x - 5 ) = 31 + 27
100 - 7 ( x - 5 ) = 58
7 ( x - 5 ) = 100 - 58
7 ( x - 5 ) = 42
x - 5 = 42 : 7
x - 5 = 6
=> x = 6 +5
=> x = 11
Vậy x = 11
b, 12 ( x - 1 ) : 3 = 43 + 23
12 ( x - 1 ) : 3 = 64 + 8
12 ( x - 1 ) : 3 = 72
12 ( x - 1 ) = 72 . 3
12 ( x - 1 ) = 216
x - 1 = 216 : 12
x - 1 = 18
=> x = 18 + 1
=> x = 19
Vậy x = 19
c, 24 + 5x = 75 : 73
24 + 5x = 72
24 + 5x = 49
5x = 49 - 24
5x = 25
=> x = 25 : 5
=> x = 5
Vậy x = 5
d, 5x - 206 = 24 . 4
5x - 206 = 16 . 4
5x - 206 = 64
5x = 64 + 206
5x = 270
=> x = 270 : 5
=> x = 54
Vậy x = 54
e, 125 = x3
53 = x3
=> x = 5
Vậy x = 5
g, 64 = x2
82 = x2
=> x = 8
Vậy x = 8