\(a,\frac{1}{2}+\frac{2}{3}x=\frac{4}{5}\)

=> \(\frac{2}{3}x=\frac{4}{5}-\frac{1}{2}=\frac{3}{10}\)

=> \(x=\frac{3}{10}:\frac{2}{3}=\frac{9}{20}\)

Vậy \(x\in\left\{\frac{9}{20}\right\}\)

\(b,x+\frac{1}{4}=\frac{4}{3}\)

=> \(x=\frac{4}{3}-\frac{1}{4}=\frac{13}{12}\)

Vậy \(x\in\left\{\frac{13}{12}\right\}\)

\(c,\frac{3}{5}x-\frac{1}{2}=-\frac{1}{7}\)

=> \(\frac{3}{5}x=-\frac{1}{7}+\frac{1}{2}=\frac{5}{14}\)

=> \(x=\frac{5}{14}:\frac{3}{5}=\frac{25}{42}\)

Vậy \(x\in\left\{\frac{25}{42}\right\}\)

\(d,\left|x+5\right|-6=9\)

=> \(\left|x+5\right|=9+6=15\)

=> \(\left[{}\begin{matrix}x+5=15\\x+5=-15\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=15-5=10\\x=-15-5=-20\end{matrix}\right.\)

Vậy \(x\in\left\{10;-20\right\}\)

\(e,\left|x-\frac{4}{5}\right|=\frac{3}{4}\)

=> \(\left[{}\begin{matrix}x-\frac{4}{5}=\frac{3}{4}\\x-\frac{4}{5}=-\frac{3}{4}\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=\frac{3}{4}+\frac{4}{5}=\frac{31}{20}\\x=-\frac{3}{4}+\frac{4}{5}=\frac{1}{20}\end{matrix}\right.\)

Vậy \(x\in\left\{\frac{31}{20};\frac{1}{20}\right\}\)

\(f,\frac{1}{2}-\left|x\right|=\frac{1}{3}\)

=> \(\left|x\right|=\frac{1}{2}-\frac{1}{3}\)

=> \(\left|x\right|=\frac{1}{6}\)

=> \(\left[{}\begin{matrix}x=\frac{1}{6}\\x=-\frac{1}{6}\end{matrix}\right.\)

Vậy \(x\in\left\{\frac{1}{6};-\frac{1}{6}\right\}\)

\(g,x^2=16\)

=> \(\left|x\right|=\sqrt{16}=4\)

=> \(\left[{}\begin{matrix}x=4\\x=-4\end{matrix}\right.\)

vậy \(x\in\left\{4;-4\right\}\)

\(h,\left(x-\frac{1}{2}\right)^3=\frac{1}{27}\)

=> \(x-\frac{1}{2}=\sqrt[3]{\frac{1}{27}}=\frac{1}{3}\)

=> \(x=\frac{1}{3}+\frac{1}{2}=\frac{5}{6}\)

Vậy \(x\in\left\{\frac{5}{6}\right\}\)

\(i,3^3.x=3^6\)

\(x=3^6:3^3=3^3=27\)

Vậy \(x\in\left\{27\right\}\)

\(J,\frac{1,35}{0,2}=\frac{1,25}{x}\)

=> \(x=\frac{1,25.0,2}{1,35}=\frac{5}{27}\)

Vậy \(x\in\left\{\frac{5}{27}\right\}\)

\(k,1\frac{2}{3}:x=6:0,3\)

=> \(\frac{5}{3}:x=20\)

=> \(x=\frac{5}{3}:20=\frac{1}{12}\)

Vậy \(x\in\left\{\frac{1}{12}\right\}\)

a) x-12:(-2)=4

=> x-12=-8

=> x=4
b ) 6-|x| = 5

=> /x/=1

=> x=1;-1
c ) 7⋮ ( x-3)

=> (x-3) thuộc Ư(7)

=> x-3=1 => x=4

=> x-3=-1 => x=2

=> x-3=7 => x= 10

=> x-3=-7 => x=-4

d ) 3⋮ ( 2x+1 )

=> (2x+1) thuộc Ư(3)

=> (2X+1)= 1 => x= 0

=> (2x+1)=-1 => x= -1

=> 2x+1= 3 => x= 1

=> 2x+1=-3 => x= -2

a) \(x-12:\left(-2\right)=4\Rightarrow x-\left(-6\right)=4\Rightarrow x=\left(-6\right)+4=-2\)

b) \(6-\left|x\right|=5\Rightarrow\left|x\right|=6-5=1\Rightarrow x=\left\{\pm1\right\}\)

c)\(7⋮x-3\Rightarrow x-3\inƯ\left(7\right)\)

\(Ư\left(7\right)=\left\{\pm1;\pm7\right\}\)

\(x=\left\{4;2;10;-4\right\}\)

d) \(3⋮2x+1\Rightarrow2x+1\inƯ\left(3\right)\)

\(Ư\left(3\right)=\left\{\pm1;\pm3\right\}\)

\(x\in\left\{0;-1;1;-2\right\}\)

a) \(\left(x-1\right):3=2^3\) \(\Leftrightarrow\) \(\left(x-1\right):3=8\) \(x+1=24\) \(\Leftrightarrow\) \(x=23\) vậy \(x=23\)

b) \(12-2\left(x+5\right)=-10\) \(\Leftrightarrow\) \(12-2x-10=-10\)

\(\Leftrightarrow\) \(-2x=-12\) \(\Leftrightarrow\) \(x=6\) vậy \(x=6\)

c) \(x-12\left(x+5\right)=-10\) \(\Leftrightarrow\) \(x-12x-60=-10\)

\(\Leftrightarrow\) \(-11x=50\) \(\Leftrightarrow\) \(x=\dfrac{50}{-11}\) vậy \(x=\dfrac{50}{-11}\)

e) \(13-x:2=10\Leftrightarrow-x:2=-3\Leftrightarrow x=\dfrac{3}{2}\)

f) \(\left|12-x\right|-7=5\)

th1 : \(x\le12\) thì \(\left|12-x\right|-7=5\) \(\Leftrightarrow\) \(12-x-7=5\) \(\Leftrightarrow\) \(-x=0\Leftrightarrow x=0\)

th2 : \(x>12\) thì \(\left|12-x\right|-7=5\) \(\Leftrightarrow\) \(x-12-7=5\) \(\Leftrightarrow\) \(x=24\) vậy \(x=0;x=24\)

i) \(x^2-7=2\Leftrightarrow x^2=9\Leftrightarrow x=3\) vậy \(x=3\)

k) \(x^3-4=-12\) \(\Leftrightarrow\) \(x^3=-8\) \(\Leftrightarrow x=-2\) vậy \(x=-2\)

a)\(\left(x-1\right):3=2^3\Rightarrow x-1=2^3.3=24\Rightarrow x=25\)

b)\(12-2\left(x+5\right)=-10\Leftrightarrow12-2x-10=-10\Rightarrow2-2x=-10\Rightarrow2x=12\Rightarrow x=6\)c)\(x-12\left(x+5\right)=-10\Rightarrow x-12x-60=-10\Rightarrow-11x-60=-10\Rightarrow-11x=-70\Rightarrow x=\dfrac{70}{-11}\)d)\(6-\left|x\right|=5\Rightarrow\left|x\right|=1\Rightarrow x=\left\{\pm1\right\}\)

Làm nốt nha

Bài 1

a.\(\frac{-3}{4}\)-y:\(\frac{1}{5}\)=\(\frac{9}{28}\)

                y:\(\frac{1}{5}\)=\(\frac{-15}{14}\)

                          y= \(\frac{-3}{14}\)

b.5^x + 5^x+2=650

5^x . 1 + 5^x + 5²=650

5^x(1+25)=650

5^x.26=650

5^x=25

x=2

1:2:3:4:5:7:9:10

Bài 1:

6) 3x + 2³ = 17 + 3²

3x + 8 = 17 + 9

3x + 8 = 26

3x = 26 - 8

3x = 18

x = 18 : 3

x = 6

Vậy x = 6

Bài 2:

3) 145 - (125 + x) = 12

125 + x = 145 - 12

125 + x = 133

x = 133 - 125

x = 8

Vậy x = 8

6) 3³ - (x - 5) = 2²

27 - (x - 5) = 4

x - 5 = 27 - 4

x - 5 = 23

x = 23 + 5

x = 28

Vậy x = 28

9) (x + 7) - 15⁰ = 202 - 19

(x + 7) - 1 = 189

x + 7 = 189 + 1

x + 7 = 190

x = 190 - 7

x - 183

Vậy x = 183

a ) + ) Xét x \(\ge\) 3 => |x - 3| = x - 3

=> |x - 3| + x - 3 = x - 3 + x - 3 = 0

<=> 2x - 6 = 0

<=> 2x = 6

=> x = 3

+ ) Xét x < 3 => |x - 3| = 3 - x

=> |x - 3| + x - 3 = 3 - x + x - 3 = 0

<=> 0 = 0 ( loại )

Vậy x = 3

ý khác tương tự

a) \(x +(x + 1) + (x + 2) + ... + (x +30) = 620\)

\(=\left(x+x+...+x+x\right)+\left(1+2+...+30\right)\)

\(=31x+465=620\)

\(=31x=620-465\)

\(=31x=155\)

\(=x=155\div31\)

\(x=5\)

b) \(2+4+6+8+....+2x = 210\)

\(\Rightarrow2.1+2.2+2.3+2.4+...+2.x\)

\(\Rightarrow2.\left(2+4+6+8+...+x\right)=210\)

\(\Rightarrow2+4+6+8+x=210\div2\)

\(\Rightarrow2+4+6+8+...+x=105\)

\(\Rightarrow x=14\)

sao đến 2+4+6+8+...+x = 105 lại => x=14 được bạn

Lời giải:

$2\frac{2}{6}x+8\frac{2}{3}=3\frac{1}{3}$

$\frac{7}{3}x=3\frac{1}{3}-8\frac{2}{3}=\frac{-16}{3}$

$x=\frac{-16}{3}: \frac{7}{3}=\frac{-16}{7}$

----------------------

$3\frac{2}{7}x-\frac{1}{8}=2\frac{3}{4}$

$\frac{23}{7}x=2\frac{3}{4}+\frac{1}{8}$

$\frac{23}{7}x=\frac{23}{8}$

$x=\frac{23}{8}: \frac{23}{7}=\frac{7}{8}$

Bài 1 : 

A = 1 + 2 + 2² + ... + 2¹¹

A = ( 1 + 2 ) + ( 2² + 2³ ) + ... + ( 2¹⁰ + 2¹¹ )

A = 3 + 2²(1+2) + ... + 2¹⁰(1+2)

A = 1.3 + 2².3 + ... + 2¹⁰.3

A = 3.(1+2²+...+2¹⁰) chia hết cho 3

Bài 2 :

2.5² + 3:71⁰ - 54:3³

= 2.25 + 3:1 - 54:27

= 50 + 3 - 2

= 49

Bài 3 :

a) ( 2x - 6 ) . 4⁷ = 4⁹

2x - 6 = 4² = 16

2x = 16

=> x = 8

b) ( 27x + 6 ) : 3 - 11 = 9

( 27x + 6 ) : 3 = 20

27x + 6 = 60

27x = 54

=> x = 2

c) 740 : ( x + 10 ) = 10² - 2.13

740 : ( x + 10 ) = 74

x + 10 = 10

=> x = 0

d) ( 15 - 6x ) . 3⁵ = 3⁶

15 - 6x = 3

6x = 12

=> x = 2

Bài 4 :

Ta có : ab + ba = ( 10a + b ) + ( 10b + a ) = ( 10a + a ) + ( 10b + b ) = 11a + 11a = 11.(a+b) chia hết cho 11 

Bài 1 : 

A = 1 + 2 + 2² + ... + 2¹¹

A = ( 1 + 2 ) + ( 2² + 2³ ) + ... + ( 2¹⁰ + 2¹¹ )

A = 3 + 2²(1+2) + ... + 2¹⁰(1+2)

A = 1.3 + 2².3 + ... + 2¹⁰.3A = 3.(1+2²+...+2¹⁰) chia hết cho 3

Bài 2 :

2.5² + 3:71⁰ - 54:3³

= 2.25 + 3:1 - 54:27

= 50 + 3 - 2= 49

Bài 3 :

a) ( 2x - 6 ) . 4⁷ = 4⁹

2x - 6 = 4² = 16

2x = 16

=> x = 8

b) ( 27x + 6 ) : 3 - 11 = 9

( 27x + 6 ) : 3 = 20

27x + 6 = 60

27x = 54

=> x = 2

c) 740 : ( x + 10 ) = 10² - 2.13

740 : ( x + 10 ) = 74

x + 10 = 10

=> x = 0

d) ( 15 - 6x ) . 3⁵ = 3⁶

15 - 6x = 3

6x = 12

=> x = 2

Bài 4 :

Ta có : ab + ba = ( 10a + b ) + ( 10b + a ) = ( 10a + a ) + ( 10b + b ) = 11a + 11a = 11.(a+b) chia hết cho 11