a. x-12=-28<=>x=-28+12=-16

b.20+8(x+3)=25.4

=>.20+8(x+3)=100

=>.8(x+3)=100-20

=>x+3=80/8

=>x=10-3=7

c.c.    {28-32+7.[1086-(-294+x)]}=-9496.

    x= cậu bấm máy lara thôi  mà

a) (125 - x) + 25 = 98

125 - x = 98 - 25

125 - x = 73

x = 125 - 73

x = 52

b) 100 : (x + 20) = 68 : 34

100 : (x + 20) = 2

x + 20 = 100 : 2

x + 20 = 50

x = 50 - 20

x = 30

c) (3x + 12) . 5 = 25 . 4 - 10

(3x + 12) . 5 = 100 - 10

(3x + 12) . 5 = 90

3x + 12 = 90 : 5

3x + 12 = 18

3x = 18 - 12

3x = 6

x = 6 : 2

x = 3

d) 210 : (2x - 3) - 20 = 10

210 : (2x - 3) = 10 + 20

210 : (2x - 3) = 30

2x - 3 = 210 : 30

2x - 3 = 70

2x = 70 + 3

2x = 73

x = 73/2

a, ( 125 - x ) + 25 = 98

⇒ 125 - x = 73

⇒ x = 52.

Vậy..

b, 100 : ( x + 20 ) = 68 : 34

⇒ 100 : ( x + 20 ) = 2

⇒ x + 20 = 50

⇒ x = 30

Vậy...

c, ( 3 . x + 12 ) . 5 = 25 . 4 - 10

⇒ ( 3 . x + 12 ) . 5 = 90

⇒ 3 .x + 12 = 18

⇒ 3x = 6

⇒ x = 2.

Vậy...

d, 210 : ( 2 .x - 3 ) - 20 = 10

⇒ ( 2 .x - 3 ) - 20 = 21

⇒ 2x - 3 = 41

⇒ 2x = 44

⇒ x = 22.

Vậy..

k cho mk nhé

20^5:4^2:125=25.4^3

hok tốt

`(3x+1)^2=25.4`

<=> `(3x+1)^2=10^2`

<=> `3x+1=10` hoặc `3x+1=-10`

<=> `x=3` hoặc `x=-11/3`

\(\left(3x+1\right)^2=25.4\\ < =>\sqrt{\left(3x+1\right)^2}=\sqrt{100}< =>3x+1=10\\ < =>3x=9\\ < =>x=3\\\)

1) x - 18 : 3 = 12

x - 6 = 12

x = 12 + 6 

x = 18

2) ( x : 3 ) - 18 = 12

x : 3 = 12 + 18

x : 3 = 30

x = 30 x 3

'x = 90

3) ( x - 3 ) : 4 = 7

x - 3 = 7 x 4

x - 3 = 28

x = 28 + 3 

x = 31

4 ) ( x : 15 ) - 3 = 25 x 4

( x : 15 ) - 3 = 100

x : 15 = 100 + 3

x : 15 = 103

x = 103 x 15

x = 1545

5) ( x - 25 ) : 9 = 0

x - 25 = 0 x 9

x - 25 = 0

x = 0 + 25

x = 25

6) 34 : ( x - 8 ) = 34

x - 8 = 34 : 34

x - 8 = 1

x = 1 + 8

x = 9

7) ( x + 4 ) x 16 = 80

x + 4 = 80 : 16

x + 4 = 5

x = 5 - 4

x = 1

\(1.x-18:3=12\)

\(x-18=12.3\)

\(x-18=36\)

\(x=36+18\)

\(x=54\)

\(\left[516-\left(25\cdot4+16\right)\right]:8-68\)

\(=\dfrac{\left[516-100-16\right]}{8}-68\)

\(=\dfrac{400}{8}-68=50-68=-18\)

a) \(18+25\times4-4^3\)

\(=18+100-64\)

\(=118-64\)

\(=54\)

b) \(275-\left(49+125\div5^3\right)\)

\(=275-\left(49+125\div125\right)\)

\(=275-\left(49+1\right)\)

\(=275-49-1\)

\(=226-1\)

\(=225\)

c) \(2015+\left(8\times15-\left(18-8\right)^2\right)\)

\(=2015+\left(8\times15-\left(10\right)^2\right)\)

\(=2015+\left(8\times15-100\right)\)

\(=2015+\left(120-100\right)\)

\(=2015+20\)

\(=2035\)

a) x*15/2/3=5

x=5*3*2*15

x=450 

đúng cho mình nha 

x . 15 : 2 : 3 = 5

x . 15 : 2 = 5 . 3

x . 15 : 2 = 15

x  . 15 = 15 x 2

x . 15 = 30

=> x = 2.

25 . 4 + (150.x) = 200

100 + (150.x) = 200

150 . x = 200 - 100

150 . x = 100

=> x = 0,6666...

`\(=\frac{5.5.4^{15}.9^9-2^9.6^{18}.6^2}{5.3.4^{12}.2.9^9.3-2^9.2^2.6^{18}.11}\)

\(=\frac{5.4^3-6^2}{3.2.3-2^2.11}\)

\(=\frac{320-36}{18-44}\)

\(=\frac{-284}{26}=\frac{-142}{13}\)

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