\(1)\)

\(a)(-50).37=-1850\)

\(b)(-20).(-14).25=280.25=7000\)

\(c)40.(-30).12=-1200.12=-14400\)

\(2)\)

\(a)\)

\(-40.[(-15)+30)]\)

\(=-40.15\)

\(=-600\)

\(b)\)

\(-5 . [(-27) - (-7)]\)

\(=-5 . [(-27)+7]\)

\(=-5 . (-20)\)

\(=100\)

\(c)\)

\(-10 . [(-28) + (-22) - 10]\)

\(=-10 . [-50 - 10]\)

\(=-10.(-60)\)

\(=600\)

Then Kiu ặ

`#3107.101107`

a,

\([(6.x - 39) \div3] .28 =5628\)

`\Rightarrow (6x - 39) \div 3 = 5628 \div 28`

`\Rightarrow (6x - 39) \div 3 = 201`

`\Rightarrow 6x - 39 = 201 . 3`

`\Rightarrow 6x - 39 = 603`

`\Rightarrow 6x = 42`

`\Rightarrow x = 42 \div 6`

`\Rightarrow x = 7`

Vậy, `x = 7`

b,

`5(7x - 45) = 2^3 . 5^2 - 3^2 . 20`

`\Rightarrow 5(7x - 45) = 8.5.5 - 9.4.5`

`\Rightarrow 5(7x - 45) = 5.(8.5 - 9.4)`

`\Rightarrow 5(7x - 45) = 5.(40 - 36)`

`\Rightarrow 7x - 45 = 5.(40 - 36) \div 5`

`\Rightarrow 7x - 45 = 4`

`\Rightarrow 7x = 49`

`\Rightarrow x = 7`

Vậy, `x = 7.`

1/6*3+1/6*9+1/9*12+........+1/30*33

=(1/3-1/6)+(1/6-1/9)+(1/9-1/12)+........+(1/30-1/33)

=1/3-1/6+1/6-1/9+1/9-1/12+........+1/30-1/33

=1/3-1/33

=10/33

nho k cho mink nha 

CHUC BAN HOC GIOI !

Gợi ý: 18 = 3.6

           54 = 6.9

           108 = 9.12

           .............

           990 = 30.33

Gấp 3 lần R rồi dùng sai phân hữu hạn.

Tự làm tiếp nhé!!!

a)  5/17 * 8/-7+8/17*-7/3+-7/3*4/17

-40/119 + 12/17 × -7/3

-40/119 + -28/17 =-236/119

b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20

(5/17+12/17)-(10/13+3/13)-11/20

-11/20

a)  5/17 * 8/-7+8/17*-7/3+-7/3*4/17

-40/119 + 12/17 × -7/3

-40/119 + -28/17 =-236/119

b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20

(5/17+12/17)-(10/13+3/13)-11/20

-11/20

C

C

Bài 1

a) 15 + 4.12 - 3²

=15 + 48 - 9

= 63 - 9

= 54

b) {[(37 + 13) : 5].2 - 45 : 5}.7 - 2022⁰

= [(50 : 5).2 - 9].7 - 1

= (10.2 - 9).7 - 1

= (20 - 9).7 - 1

= 11.7 - 1

= 77 - 1

= 76

Bài 2

a) 13x + 3 = 16

13x = 16 - 3

13x = 13

x = 13 : 13

x = 1

b) 2x - 138 = 2⁴ : 2³

2x = 2 + 138

2x = 140

x = 140 : 2

x = 70