đùa nhau à

?

`123-x=38`

`=> x= 123-38`

`=>x=85`

Vậy `x=85`

__

`(x+15) -7=33`

`=>x+15=33+7`

`=>x+16= 40`

`=>x=40-16`

`=>x=24`

Vậy `x=24`

__

`3^(x+3) -13=230`

`=> 3^(x+3) = 230+13`

`=>3^(x+3)=243`

`=> 3^(x+3)=3^5`

`=> x+3=5`

`=>x=5-3`

`=>x=2`

Vậy `x=2`

a) 7(x - 5) + 2 = 51

\(\Leftrightarrow\) 7(x - 5) = 51 - 2

\(\Leftrightarrow\) 7(x - 5) = 49

\(\Leftrightarrow\) x - 5 = 49 : 7

\(\Leftrightarrow\) x - 5 = 7

\(\Leftrightarrow\) x = 7 + 5

\(\Leftrightarrow\) x = 12.

Vậy x = 12.

k) 2412 : (3x + 147) = |-38| + (-26)

\(\Leftrightarrow\) 2412 : (3x + 147)= 38 + (-26)

\(\Leftrightarrow\) 2412 : (3x + 147)= 12

\(\Leftrightarrow\) 3x + 147 = 2412 : 12

\(\Leftrightarrow\) 3x + 147 = 201

\(\Leftrightarrow\) 3x = 201 - 147

\(\Leftrightarrow\) 3x = 54

\(\Leftrightarrow\) x = 54 : 3

\(\Leftrightarrow\) x = 18.

Vậy x = 18.

I) 4824 : (4x + 137) = |-59| + (-35)

\(\Leftrightarrow\) 4824 :(4x + 137) = 59 + (-35)

\(\Leftrightarrow\) 4824 :(4x + 137) = 24

\(\Leftrightarrow\) 4x + 137 = 4824 : 24

\(\Leftrightarrow\) 4x + 137 = 201

\(\Leftrightarrow\) 4x = 201 - 137

\(\Leftrightarrow\) 4x = 64

\(\Leftrightarrow\) x = 64 : 4

\(\Leftrightarrow\) x = 16.

Vậy x = 16.

c) |-123| - 5(x - 3) = (-28) + 66

\(\Leftrightarrow\) 123 - 5(x - 3) = 38

\(\Leftrightarrow\) 5(x - 3) = 123 - 38

\(\Leftrightarrow\) 5(x - 3) = 85

\(\Leftrightarrow\) x - 3 = 85 : 5

\(\Leftrightarrow\) x - 3 = 17

\(\Leftrightarrow\) x = 17 + 3

\(\Leftrightarrow\) x = 20.

Vậy x = 20.

m) 7x - 4 . 6 = 2058

\(\Leftrightarrow\) 7x - 24 = 2058

\(\Leftrightarrow\) 7x = 2058 + 24

\(\Leftrightarrow\) 7x = 2082

\(\Leftrightarrow\) x = 2082 : 7

\(\Leftrightarrow\) x = \(\frac{2058}{7}\).

Vậy x = \(\frac{2058}{7}\).

Phần b) ra phân số nên mình để mai làm và cả những bài còn lại nữa.

Chúc bạn học tốt !!!

---------------NHANH NHA MK ĐANG CẦN GẤP--------------

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

Lời giải:
a. $15-(-2x)=22+3x$

$15+2x=22+3x$

$15-22=3x-2x$

$-7=x$

b.

$5(17-3x)+24=4$

$5(17-3x)=4-24=-20$

$17-3x=-20:5=-4$

$3x=17-(-4)=21$

$x=21:3=7$

c.

$42:(x^2+5)=3$

$x^2+5=42:3=14$

$x^2=14-5=9=3^2=(-3)^2$

$\Rightarrow x=3$ hoặc $x=-3$

d.

$73-3x^2=5^6:(-5)^4=(-5)^6:(-5)^4=(-5)^2=25$

$3x^2=73-25=48$
$x^2=48:3=16=4^2=(-4)^2$

$\Rightarrow x=4$ hoặc $x=-4$

1)

a) 2x + 5 = 3⁴ : 3²

2x + 5 = 3²

2x + 5 = 9

2x = 9 - 5

2x = 4

x = 4 : 2

x = 2

b) (3x - 24).73 = 2.74

(3x - 24).73 = 148

3x - 24 = 148/73

3x = 148/73 + 24

3x = 1900/73

x = 1900/73 : 3

x = 1900/219

c) [3.(42 - x)] + 15 = 23.3

126 - 3x + 15 = 69

141 - 3x = 69

3x = 141 - 69

3x = 72

x = 72 : 3

x = 24

d) 126 + (132 - x) = 300

132 - x = 300 - 126

132 - x = 174

x = 132 - 174

x = -42

2)

a) 120 - (x + 55) = 60

x + 55 = 120 - 60

x + 155 = 60

x = 60 - 55

x = 5

b) (7x - 11).3 = 25.52 + 200

(7x - 11).3 = 1500

7x - 11 = 1500 : 3

7x - 11 = 500

7x = 500 + 11

7x = 511

x = 511 : 7

x = 73

c) 2x + 2x + 4 = 544

4x = 544 - 4

4x = 540

x = 540 : 4

x = 135

g: =>3x-10=200

hay x=70

c) (7x + x – 28) :100 – 38 = 9

<=> 8x - 28 = 4700

<=> x = 591

a) \(3x-18.28:14=308\)

\(=>3x-36=308\)

\(=>3x=344\)\(\)

\(=>x=\frac{344}{3}\)

\(\)b)\(38+\left|x\right|=\left(-12\right)+65\)

\(=>38+\left|x\right|=53=>\left|x\right|=15=>\orbr{\begin{cases}x=15\\x=-15\end{cases}}\)

c)\(15+3.\left(x-1\right):5=30\)

\(=>15+3.\left(x-1\right)=150\)

\(=>3.\left(x-1\right)=135\)

\(x-1=45=>x=46\)

d) \(5.\left(7-3x\right)+7.\left(2+2x\right)=1\)

\(=>35-15x+14+14x=1\)

\(=>49-x=1=>x=48\)

e)\(3.\left(x-7\right)=21\)

\(=>x-7=7=>x=14\)

g)\(\left[\left(6x-72\right):2-84\right]:28=5628\)

\(\left(6x-72\right):2-84=157584\)

\(\left(6x-72\right):2=157668\)

\(6x-72=315336\)

\(6x=315408=>x=52568\)

h)\(123-5\left(x+4\right)=28\)

\(5.\left(x+4\right)=95\)

\(x+4=19=>x=15\)

p)\(14.\left(x-3\right)-138=73\)

\(14.\left(x-3\right)=211\)

\(x-3=\frac{211}{14}=>x=\frac{253}{14}\)

\(t\)

\(\left|x\right|-5=2\)

\(\left|x\right|=7=>\orbr{\begin{cases}x=7\\x=-7\end{cases}}\)

v)\(4x-72=\left|100-8.25\right|\)

\(4x-72=\left|-100\right|\)

\(4x-72=100=>4x=172=>x=43\)

cậu có thể tham khảo bài làm trên đây ạ, chúc cậu học tốt ^^

123 - 5(x + 4) = 38

=> 5(x + 4) = 85

=> x + 4 = 17

=> x = 13

vậy_

(3x - 24).73 = 2.7

=> (3x - 24).73 = 14

=> 3x - 24 = 1022

=> 3x = 1046

=> x = 1046/3