Đặt A = 2³ + 2⁴ + ... + 2^x

=> 2A = 2⁴ + 2⁵ + ... + 2^{x + 1}

Khi đó 2A - A = (2⁴ + 2⁵ + ... + 2^{x + 1}) - (2³ + 2⁴ + ... + 2^x)

          =>    A  = 2^{x + 1} - 2³ = 2^{x + 1} - 8

Khi đó 2³ + 2⁴ + ... 2^x = 504

<=> 2^{x + 1} - 8 = 504

=> 2^{x + 1} = 512

=> 2^{x + 1} = 2⁹

=> x + 1 = 9

=> x = 8

Vậy x = 8

x / (2/7) = x * 7/2

rồi lấy x làm thừa số chung, rồi tính thừa số kia, rồi tìm x

584 x 2 + 236 x 3 + 324 x 4

= 1168 + 708 + 1296

= 3172

  584 x 2 + 236 x 3 + 324 x 4

= 1168 + 708 + 1296

= 1876 + 1296

= 3172

( 7.x - 15 ) : 3 = 2

7.x - 15 = 6

7.x = 6 + 15

7.x = 21

  x = 3

không biết vì chưa học

88 - 3 ( 7 + x ) = 64

3 ( 7 + x ) = 88 - 64

3 ( 7 + x ) = 24

7 + x = 8

      x = 1

(7.x -15):3=2

7.x-15=2.3

7.x-15=6

7.x=6+15

7.x=21

x=21:7

x=3

12.(x+37)=504

x+37=504:12

x+37=42

x=42-37

x=5

88-3(7+x)=64

3(7+x)=88-64

3(7+x)=24

7+x=24:3

7+x=8

x=8-7

x=1

dấu . là nhân nhé

Sửa đề : 

\(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x}+\frac{1}{x\left(x+1\right)}=\frac{504}{1009}\)

\(\Rightarrow\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}=\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{2}-\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{2018}\)

\(\Leftrightarrow x=2018-1\)

\(\Leftrightarrow x=2017\)

Vậy ...

Sửa đề  \(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x\left(x+1\right)}=\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+....+\frac{1}{x}-\frac{1}{x+1}=\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{2}-\frac{504}{1009}\)

\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{2018}\)

\(\Leftrightarrow x=2017\)

x = 2017 nha bạn 

i love you

Tran thi quynh trang tỏ tình công khai ak??

mik không biết ghi gì nên ghi đại

a) \(\left(x-\frac{1}{3}\right)^2-\frac{1}{4}=0\)

\(\Rightarrow\left(x-\frac{1}{3}\right)^2=0+\frac{1}{4}=\frac{1}{4}\)

\(\Rightarrow x-\frac{1}{3}=\sqrt{\frac{1}{4}}=\frac{1}{2}\)

\(\Rightarrow x=\frac{1}{2}+\frac{1}{3}=\frac{5}{6}\)

Nếu x = 0 => 2^0 + 624 = 5^y => 625 = 5^y => 5^4 = 5^y => y = 4

Nếu x > 0 => 2^x + 624 chẵn mà 5^y lẻ => không có x; y thoả mãn

Vậy x = 0; y = 4

Bạn Trần Như trả lời thiếu nhé

\(\left(x-\frac{1}{3}\right)^2=\frac{1}{4}\Leftrightarrow\orbr{\begin{cases}x-\frac{1}{3}=\frac{1}{2}\Rightarrow x=\frac{5}{6}\\x-\frac{1}{3}=-\frac{1}{2}\Rightarrow x=-\frac{1}{6}\end{cases}}\)

Vậy \(x=\frac{5}{6}\)hoặc\(x=-\frac{1}{6}\)

a)271.11

\(a.271.11-17.11\)

\(=\left(271-17\right).11\)

\(=254.11\)

\(=2794\)

1/\(a,271\cdot11-17\cdot11=11\left(271-17\right)=11\cdot200=2200\)
\(b,136\cdot23+136\cdot17+40\cdot36=136\left(23+17\right)+40\cdot36=136\cdot40+40\cdot36=40\left(136+36\right)=40\cdot172=6880\)
2/\(a,17\cdot6^2-230:x=584\Rightarrow17\cdot36-230:x=584\Rightarrow612-230:x=584\Rightarrow230:x=612-584=28\Rightarrow x=230:28=\frac{230}{28}=\frac{115}{14}\)
\(b,293-2^3\cdot3^3+x:25=80\Rightarrow293-8\cdot27+x:25=80\Rightarrow293-216-80+x:25=0\Rightarrow x:25=3\Rightarrow x=3\cdot25=75\)

\(c,4\cdot5^2-x:2=9\Rightarrow4\cdot25-9=x:2\Rightarrow x:2=91\Rightarrow x=91\cdot2=182\)