x=29/3=9.667

Bài này toán lớp 7 rồi bạn.

Cái này mình nghĩ bạn nên truyền lại cho các bạn vì mình thấy nó rắt có ích có thể sẽ có nhiều bạn cần tới nó cảm ơn lời khuyên của bạn .

Thanks!^^

\(\dfrac{7}{10}:x=\dfrac{1}{2}\\ x=\dfrac{7}{10}:\dfrac{1}{2}\\ x=\dfrac{7}{5}\)

\(\dfrac{7}{10}\): \(x\) = \(\dfrac{1}{2}\)

       \(x\) = \(\dfrac{7}{10}\): \(\dfrac{1}{2}\)

       \(x\) = \(\dfrac{7}{5}\)

\(2.3^x+5.3^x.3=153\Leftrightarrow2.3^x+15.3^x=153\)

\(\Leftrightarrow17.3^x=153\Leftrightarrow3^x=9\Leftrightarrow x=2\)

\(\Leftrightarrow2.3^x+5.3.3^x=153\)

\(\Leftrightarrow17.3^x=3^2.17\)

\(\Leftrightarrow3^x=3^2\Rightarrow x=2\)

\(A=\dfrac{3x-1}{x+2}\inℕ\left(x\inℕ;x\ne-2\right)\)

\(\Rightarrow3x-1⋮x+2\)

\(\Rightarrow3x-1-3\left(x+2\right)⋮x+2\)

\(\Rightarrow3x-1-3x-6⋮x+2\)

\(\Rightarrow-7⋮x+2\)

\(\Rightarrow x+2\in U\left(7\right)=\left\{1;7\right\}\)

\(\Rightarrow x\in\left\{-1;5\right\}\)

\(\Rightarrow x\in\left\{5\right\}\left(x\inℕ\right)\)

Đặt \(A=2^x+2^{x+1}+...+2^{x+2021}=2^{x+2026-16}\)

Đặt \(2A=2^{x+1}+2^{x+2}+...+2^{x+2022}=2^{x+2027+32}\)

Ta lấy \(2A-A=2^{x+2022}-2^x=2^{2026-16}\)

\(\Rightarrow x=4\)

Vậy \(x=4\)

\(2VT=2^{x+1}+2^{x+2}+2^{x+3}+...+2^{x+2022}\)

\(VT=2VT-VT=2^{x+2022}-2^x\)

\(\Rightarrow2^{x+2022}-2^x=2^{2026}-16\)

\(\Leftrightarrow2^{2022}.2^x-2^x=2^{2026}-2^4\)

\(\Leftrightarrow2^x\left(2^{2022}-1\right)=2^4\left(2^{2022}-1\right)\)

\(\Leftrightarrow2^x=2^4\Rightarrow x=4\)

\(\left(7x-11\right)^3=2^5.5^2+2.10^2\)

\(\Rightarrow\left(7x-11\right)^3=32.25+2.100\)

\(\Rightarrow\left(7x-11\right)^3=800+200\)

\(\Rightarrow\left(7x-11\right)^3=1000\)

\(\Rightarrow\left(7x-11\right)^3=10^3\)

\(\Rightarrow7x-11=10\)

\(\Rightarrow7x=21\)

\(\Rightarrow x=3\)

(7\(x\) - 11)³ = 2⁵.5² + 2.10²

(7\(x\) - 11)³ = 1000

(7\(x\) - 11)³ = 10³

7\(x\) - 11 = 10

7\(x\)        = 10 + 11

7\(x\)        = 21

   \(x\)       = 21:7

   \(x\)        = 3

          \(\dfrac{x-6}{1998}\) + \(\dfrac{x-4}{2000}\) = \(\dfrac{x-2000}{4}\) + \(\dfrac{x-1998}{6}\)

\(\dfrac{x-6}{1998}\) - 1 + \(\dfrac{x-4}{2000}\) - 1 = \(\dfrac{x-2000}{4}\) - 1 + \(\dfrac{x-1998}{6}\) - 1

\(\dfrac{x-6-1998}{1998}\) + \(\dfrac{x-4-2000}{2000}\)  = \(\dfrac{x-2000-4}{4}\) + \(\dfrac{x-1998-6}{6}\)

\(\dfrac{x-2004}{1998}\)  + \(\dfrac{x-2004}{2000}\) = \(\dfrac{x-2004}{4}\) + \(\dfrac{x-2004}{6}\)

(\(x-2004\)).[\(\dfrac{1}{1998}\) + \(\dfrac{1}{2000}\) - \(\dfrac{1}{4}\) - \(\dfrac{1}{6}\)] = 0

\(x\) - 2004 = 0

\(x\)             = 2004

có cái câu này nữa ah :(

HCN có nửa chu vi là 180m nếu Cr + 3m  và giảm chiều dài 3m ta đc hình vuông.DT hình vuông là

Hỏi vào 1 post khác đi e ơi

\(80-7\left(x-7\right)=95-3^2.6\)

\(\Rightarrow80-7\left(x-7\right)=95-54\)

\(\Rightarrow80-7\left(x-7\right)=41\)

\(\Rightarrow7\left(x-7\right)=80-41\)

\(\Rightarrow7\left(x-7\right)=39\)

\(\Rightarrow x-7=\dfrac{39}{7}\)

\(\Rightarrow x=\dfrac{39}{7}+7\)

\(\Rightarrow x=\dfrac{39}{7}+\dfrac{49}{7}\)

\(\Rightarrow x=\dfrac{88}{7}\)

\(80-7\left(x-7\right)=95-3^2.6\)

\(80-7\left(x-7\right)=95-9.6\)

\(80-7\left(x-7\right)=95-54\)

\(80-7\left(x-7\right)=41\)

\(7\left(x-7\right)=80-41\)

\(7\left(x-7\right)=49\)

\(x-7=49:7\)

\(x-7=7\)

\(x=7+7\)

\(\Rightarrow x=14\)