a) x= 115

b) x= \(\frac{17}{9}\)

c) x= \(\frac{9}{3}\)

câu 1 200-(x+15)=70

x+15=200-70

x+15=130

x=130-15

x=115

vậy x=115

câu 2: 70-3(4-3x)=75

3(4-3x)=70-75

3(4-3x)=-5   (âm 5 nhé)

4-3x=-5:3

4-3x=-5/3 (âm 5 phần 3 nhé)

3x=4-(-5/3)

3x=17/3

x=17/3 : 3

x=17/9

vậy x=17/9

câu 3: 2(3x+1)-12=8

2(3x+1)=8+12

2(3x+1)=20

3x+1 =20:2

3x+1=10

3x=10-1

3x=9

x=9:3

x=3

vậy x=3

chúc bạn học tốt

a. 200 - (x + 15) = 70

x + 15                 = 200 - 70

x                         = 130 - 15

x                         = 115

b. 70 - 3.(4 - 3x) = 75

3.(4 - 3x)            = 70 - 75

4 - 3x                  = -5 : 3

3x                       = 4 + \(\frac{5}{3}\)

x                         = \(\frac{17}{3}:3\)

x                         = \(\frac{17}{9}\)

c. 2 .(3x + 1) -12 = 8

2. (3x + 1)           = 8 + 12

3x + 1                 = 20 : 2

3x                       = 10 - 1

x                         = 9 : 3

x                         = 3

Khiếp

2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40 
= 2. 53 . 9 . 3 + 2. 3 .9 .87 - 3 .2 .9 .40
= 54.53+54.87-54.40
=54(53+87-40)
=54. 100=5400

12 . 25 + 29 . 25 + 59 . 25 
= 25 . ( 12+29+59)
=25 . 90
=2250

43 . 37 + 93 . 43 + 57 . 61 + 69 . 57 
= 43.(37+93)+57(61+69)
=43.130+57.130
=130.(43+57)
=130.100
=13 000

12 . 53 + 53 . 172 - 53 
=53(12+172-1)
=53.184
=9752

35 . 54 + 35 . 58 + 65 . 75 + 65 . 45 
=35(54+58)+65(75+45)
=35.112+65.120
=3920+7800
=11720

39 . 8 + 70 . 3 + 31 . 8 
=8(39+31)+70.3
=8.70+70.3
=70.(8+3)
=70.11
=770

2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40

= ( 2 . 27 ) . 53 + ( 6 . 9 ) . 87 - ( 3 . 18 ) . 40

= 54 . 53 + 54 . 87 - 54 . 40

= 54(53+87-40)

= 5400

12 . 25 + 29 . 25 + 59 . 25

= 25( 12 + 29 + 59 )

= 2500

43 . 37 + 93 . 43 + 57 . 61 + 69 . 57

= 43( 37 + 93 ) + 57(61 + 69 )

= 5590 + 7410

= 13000

12 . 53 + 53 . 172 - 53 

= 53( 12 + 172 ) - 53

= 9752 - 53

= 9699

35 . 54 + 35 . 58 + 65 . 75 + 65 . 45

= 35( 54 + 58 ) + 65( 75 + 45 )

= 3920 + 7800

= 11720

bạn tách từng bài ra bn

tl câu hỏi trên cho mik ik

giải phương trình làm dell gì, lớp 8 mà

a) x = 2 7                         b) x = 2.

c) x = 2                          d) x = 1.

a: 2/3;4/6

b: 5/3; 25/15; 50/30; 75/45; 125/75

a,\(\dfrac{2}{3},\dfrac{4}{6}\)

b,\(\dfrac{5}{3},\dfrac{25}{15},\dfrac{50}{30},\dfrac{75}{45},\dfrac{125}{75}\)

kh hiểu bn ơi

`4x=2+xx+1x<=>4x=2+3x<=>4x-3x=2<=>1x=2<=>x=2`

Dễ

 Thế

Mà

Cũnhoir

Dc

Ạ

Chịu

Chắc

Phải

Ngu 

Lamqs

Mới

Hỏi

Câu

Này

a.75-(3.5^2-4.2^3)

=75-(-5)

=80

b.-/-12/+12-(-24)

= - 12 + 12 - 24

=0-24

=-24

c.17.85+15.17-120

=17.(85+15)-120

=17.100-120

=1700-120

=1580

bài 2: tìm x

a. 70-5.(x-3)=45

5.(x-3)=70-45=25

x-3=25:5=5

x=5+3=8

vậy x=8

nhanh giùm mình được không

Bài 1: 

a) Ta có: \(P=1+\dfrac{3}{x^2+5x+6}:\left(\dfrac{8x^2}{4x^3-8x^2}-\dfrac{3x}{3x^2-12}-\dfrac{1}{x+2}\right)\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}:\left(\dfrac{8x^2}{4x^2\left(x-2\right)}-\dfrac{3x}{3\left(x-2\right)\left(x+2\right)}-\dfrac{1}{x+2}\right)\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}:\left(\dfrac{4}{x-2}-\dfrac{x}{\left(x-2\right)\left(x+2\right)}-\dfrac{1}{x+2}\right)\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}:\dfrac{4\left(x+2\right)-x-\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}\cdot\dfrac{\left(x-2\right)\left(x+2\right)}{4x+8-x-x+2}\)

\(=1+3\cdot\dfrac{\left(x-2\right)}{\left(x+3\right)\left(2x+10\right)}\)

\(=1+\dfrac{3\left(x-2\right)}{\left(x+3\right)\left(2x+10\right)}\)

\(=\dfrac{\left(x+3\right)\left(2x+10\right)+3\left(x-2\right)}{\left(x+3\right)\left(2x+10\right)}\)

\(=\dfrac{2x^2+10x+6x+30+3x-6}{\left(x+3\right)\left(2x+10\right)}\)

\(=\dfrac{2x^2+19x-6}{\left(x+3\right)\left(2x+10\right)}\)