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Bài 1 :

a) \(...=5^5:5^4=5\)

b) \(...=7^8:7^9=\dfrac{1}{7}\)

c) \(...=2^{15}:\left(2^6.2^5\right)=2^{15}:2^{11}=2^4=16\)

d) \(...=3^{28}:3^{26}=3^2=9\)

Bài 2 :

a) \(...=3^2.3^3:3^4=3^5:3^4=3\)

b) \(...=10^9-10^9=0\)

c) \(...=5^{10}.5^{30}:5^{12}=5^{40}:5^{12}=5^{28}\)

d) \(...=5^{12}:5^9=5^3=125\)

a)-16=7-x-25-7

-25-x=-16

x=-25-(-16)

x=-9

b)8x-x=10+4

7x=14

x=14:7

x=2

a,x=-9

b,x=2

tick nhe

a) x - (17 - 8) = 5 + (10 - 3x)

x - 17 + 8 = 5 + 10 - 3x

x + 3x = 5 + 10 + 17 - 8

4x = 24

x = 24 : 4

x = 6

b) 25 - (30 + x) = x - (27 - 8)

25 - 30 - x = x - 27 + 8

-x - x = -27 + 8 - 25 + 30

-2x = -14

x = (-14) : (-2)

x = 7

c) (x - 12) - 15 = (20 - 7) - (18 + x)

x - 12 - 15 = 20 - 7 -18 - x

x + x = 20 - 7 - 18 + 12 + 15

2x = 22

x = 22 : 2

x = 11

d) 9 - 25 = (7 - x) - (25 + 7)

9 - 25 = 7 - x - 25 - 7

x = 7 - 25 - 7 - 9 +25

x = -9

b. -6x=18

=> x = 18 : (-6)

=> x = -3

c. 35-3.|x|=5.(2³-4)

=> 35-3.|x|=5.(8-4)

=> 35-3.|x|=5.4

=> 35-3.|x|=20

=> 3.|x|=35-20

=> 3.|x|=15

=> |x|=5

=> x \(\in\){-5; 5}

d. => 10+2.|x|=2.(9-1)

=> 10+2.|x|=2.8

=> 10+2.|x|=16

=> 2.|x|=16-10

=> 2.|x|=6

=> |x|=3

=> x \(\in\){-3; 3}

a. 9 - 25 = ( 7 - x ) - ( 25 + 7 )

=> -16 = 7 - x - 32

=> x = 7 - 32 + 16

=> x = -9.

9-25=(7-x)-(25+7)
9-25=7-x-25-7
=> 9-25-7+25+7=-x
=> x=-9 

a) \(5\left(x+7\right)-10=2^3\cdot5\)

\(\Rightarrow5\left(x+7\right)-10=40\)

\(\Rightarrow5\left(x+7\right)=40+10\)

\(\Rightarrow x+7=\dfrac{50}{5}\)

\(\Rightarrow x+7=10\)

\(\Rightarrow x=10-7\)

\(\Rightarrow x=3\)

b) \(9x-2\cdot3^2=3^4\)

\(\Rightarrow9x-18=81\)

\(\Rightarrow9x=81+18\)

\(\Rightarrow9x=99\)

\(\Rightarrow x=\dfrac{99}{9}\)

\(\Rightarrow x=11\)

c) \(5^{25}\cdot5^{x-1}=5^{25}\)

\(\Rightarrow5^{x-1}=5^{25}:5^{25}\)

\(\Rightarrow5^{x-1}=1\)

\(\Rightarrow5^{x-1}=5^0\)

\(\Rightarrow x-1=0\)

\(\Rightarrow x=1\)

a) 5(�+7)−10=23⋅55(x+7)−10=23⋅5

$\Rightarrow 5\left(x+7\right)-10=40$

$\Rightarrow 5\left(x+7\right)=40+10$

⇒�+7=505⇒x+7=550​

$\Rightarrow x+7=10$

$\Rightarrow x=10-7$

$\Rightarrow x=3$

b) 9�−2⋅32=349x−2⋅32=34

$\Rightarrow 9x-18=81$

$\Rightarrow 9x=81+18$

$\Rightarrow 9x=99$

⇒�=999⇒x=999​

$\Rightarrow x=11$

c) 525⋅5�−1=525525⋅5x−1=525

⇒5�−1=525:525⇒5x−1=525:525

⇒5�−1=1⇒5x−1=1

⇒5�−1=50⇒5x−1=50

$\Rightarrow x-1=0$

$\Rightarrow x=1$

a) [ 25 - ( x + 1,85 ) ] : 3 = 7

[ 25 - ( x + 1,85) ] = 7x3

[ 25 - ( x + 1,85 ) ] = 21

x + 1,85= 25-21

x + 1,85= 4

x= 4-1,85

x= 2,15

a) [25 - (x + 1,85)] : 3 = 7

=> 25 - (x + 1,85)       = 3 x 7

=> 25 - (x + 1,85)       = 21

=> x + 1,85                 = 25 - 21

=> x + 1,85                  = 4

=> x                             = 4 - 1,85

=> x                             = 2,15

b) 420 : [75  - (x - 10)] = 21

=> 75 - (x - 10) = 420 : 21

=> 75 - (x - 10) = 20

=> x - 10           = 75 - 20

=> x - 10           = 55

 => x                  = 55 + 10

=> x                   = 65

b) 420 : [ 75 - ( x-10 ) ] = 21

[ 75 - ( x-10) ]= 420:21

[ 75 - ( x-10) ] = 20

( x- 10) =75-20

 x-10 = 55

x= 55+10

x=65