a: \(x-\dfrac{10}{3}=\dfrac{7}{15}\cdot\dfrac{3}{5}\)

=>\(x-\dfrac{10}{3}=\dfrac{21}{75}=\dfrac{7}{25}\)

=>\(x=\dfrac{7}{25}+\dfrac{10}{3}=\dfrac{21+250}{75}=\dfrac{271}{75}\)

b: \(x+\dfrac{3}{22}=\dfrac{27}{121}\cdot\dfrac{9}{11}\)

=>\(x+\dfrac{3}{22}=\dfrac{243}{1331}\)

=>\(x=\dfrac{243}{1331}-\dfrac{3}{22}=\dfrac{123}{2662}\)

c: \(\dfrac{8}{23}\cdot\dfrac{46}{24}-x=\dfrac{1}{3}\)

=>\(\dfrac{8}{24}\cdot\dfrac{46}{23}-x=\dfrac{1}{3}\)

=>\(\dfrac{2}{3}-x=\dfrac{1}{3}\)

=>\(x=\dfrac{2}{3}-\dfrac{1}{3}=\dfrac{1}{3}\)

d: \(1-x=\dfrac{49}{65}\cdot\dfrac{5}{7}\)

=>\(1-x=\dfrac{49}{7}\cdot\dfrac{5}{65}=\dfrac{7}{13}\)

=>\(x=1-\dfrac{7}{13}=\dfrac{6}{13}\)

\(\frac{2}{3}.x=\frac{1}{3}\)1) x-\(\frac{10}{3}\)=\(\frac{7}{15}.\frac{3}{5}\)

x-10/3=7/25

x=7/25+10/3

x=\(\frac{271}{75}\)

2)\(\frac{8}{23}.\frac{46}{24}.x=\frac{1}{3}\)

2/3.x=1/3

x=1/3:2/3

x=1/2

Tìm x

a, 5x - 10 . (-7) = 15 . (-3)

5x + 70 = -45

5x = -45 - 70

5x = -115

x = -115 : 5

x = -23

Vậy x = -23.

b, 2x + 12 = -8

2x = -8 - 12

2x = -20

x = -20 : 2

x = -10

Vậy x = -10.

c, 3x - 5 = -20

3x = -20 + 5

3x = -15

x = -15 : 3

x = -5

Vậy x = -5.

d, 2x - (-12) = -8 . 23

2x + 12 = -184

2x = -184 - 12

2x = -196

x = -196 : 2

x = -98

Vậy x = -98.

e, x² = 49

x² = 7² = (-7)²

=> x = 7 hoặc x = -7.

Vậy x thuộc {-7 ; 7}

i, (x - 2)² + 1 = 65

(x - 2)² = 65 - 1

(x - 2)² = 64

(x - 2)² = 8² = (-8)²

=> x - 2 = 8 hoặc x - 2 = -8

=> x = 10 hoăc x = -6

Vậy x thuộc {-6 ; 10}.

g, 2 (x - 3)² - 5 = 5 . (-3)²

2 (x - 3)² - 5 = 5 . 9

2 (x - 3)² - 5 = 45

2 (x - 3)² = 45 + 5

2 (x - 3)² = 50

(x - 3)² = 50 : 2

(x - 3)² = 25

(x - 3)² = 5² = (-5)²

=> x - 3 = 5 hoặc x - 3 = -5

=> x = 8 hoặc x = -2

Vậy x thuộc {-2 ; 8}.

a) 5x - 10.(-7)=15.(-3)      b) 2x+12=-8     c) 3x-5=-20        d)2x-(-12)=-8.23      e)\(^{x^2}\)=49      i)\(\left(x-2\right)^2+1\)=65

 5x+70=-45                          2x=-8-12           3x=-20+5           2x+12=-184                 x=7            \(\left(x-2\right)^2\) =64

5x=-45-70                            2x=-20               3x=-15              2x=-184-12                                      X-2            =8

5x=-115                                 x=-20:2             x=-15:3            2x=-186                                             x                =10

x=-23                                      x=-10                x=-5                   x=-93

g)\(2.\left(x-3\right)^2-5=5.\left(-3\right)^2\)

   \(2\left(x-3\right)^2-5=30\)

 \(2.\left(x-3\right)^2=35\)

\(2.\left(x^2-2x.3+3^2\right)=35\)

\(2x^2-24x+18=35\)

\(2x^2-24x=17\)

\(2x\left(x-12\right)=17\)

\(\orbr{\begin{cases}2x=17\\x-12=17\end{cases}}\orbr{\begin{cases}x=\frac{17}{2}\\x=29\end{cases}}\)

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1 + 2 + 3 + ... + n = n(n + 1)/2

1 + 3 + 5 + 7 + ... + 2n − 1 = n²

2 + 4 + 6 + 8 + ... + 2n = n(n + 1)

a) 49.(-34)+(-65).49-49 = 49. (-34-65-1)= 49. (-100)= -4900

b) -268-(-47-168)-147 = (-268 + 168) - (147 - 47)= -100 -100=-200

c) (-2)².(-3)-[(-1)²⁰²⁴+8]:(-3)² = 4. (-3) - [1 +8]:9 = -12 - 9:9 = -12 - 1 = -13

d) 67-[8+7.3² -24:6+(9-7)³]:15 = 67 - [8 + 7.9 - 4 + 2³ ] : 15

= 67 - [8+63-4+8]:15 = 67 - 75:15 = 67 - 5 = 62

`2 : x = x : 8/49`

`<=> x^2 = 16/49`

`<=> x = +-4/7`

5 + ( x + 27 ) = 64

a) \(\Rightarrow x+27=59\Rightarrow x=32\)

b) \(\Rightarrow x-2=39\Rightarrow x=41\)

c) \(\Rightarrow x+5=-322\Rightarrow x=-327\)

d) \(\Rightarrow5x=35\Rightarrow x=7\)

e) \(\Rightarrow4\left(x-5\right)=56\Rightarrow x-5=14\Rightarrow x=19\)

f) \(\Rightarrow15+x=37\Rightarrow x=22\)

g) \(\Rightarrow7\left(13-x\right)=35\Rightarrow13-x=5\Rightarrow x=8\)

h) \(\Rightarrow10\left(x+1\right)=100\Rightarrow x+1=10\Rightarrow x=9\)

Ai giải hộ e với e phải đi học

a. 8 + (x - 9) = 125 - 64

8 + (x - 9) = 61

x - 9 = 53

x = 62

b. 5 x (X + 7) - 10 = 8 x 5

5 x (X + 7) - 10 = 40

5 x (X + 7) = 50

X + 7 = 10

X = 3