\(3,8:\left(2x\right)=\frac{1}{4}:2\frac{2}{3}\)

\(3,8:\left(2x\right)=\frac{3}{32}\)

\(\Rightarrow2x=3,8:\frac{3}{32}\)

\(\Rightarrow x=\frac{608}{15}:2=\frac{304}{15}\)

\(\left(a\right)\) tức là bài a hay là gt trog tỉ lệ thức v pn?

a)

\((3x-7)^5=0\Rightarrow 3x-7=0\Rightarrow x=\frac{7}{3}\)

b)

\(\frac{1}{4}-(2x-1)^2=0\)

\(\Leftrightarrow (2x-1)^2=\frac{1}{4}=(\frac{1}{2})^2=(-\frac{1}{2})^2\)

\(\Rightarrow \left[\begin{matrix} 2x-1=\frac{1}{2}\\ 2x-1=\frac{-1}{2}\end{matrix}\right.\Rightarrow \Rightarrow \left[\begin{matrix} x=\frac{3}{4}\\ x=\frac{1}{4}\end{matrix}\right.\)

c)

\(\frac{1}{16}-(5-x)^3=\frac{31}{64}\)

\(\Leftrightarrow (5-x)^3=\frac{1}{16}-\frac{31}{64}=\frac{-27}{64}=(\frac{-3}{4})^3\)

\(\Leftrightarrow 5-x=\frac{-3}{4}\)

\(\Leftrightarrow x=\frac{23}{4}\)

d)

\(2x=(3,8)^3:(-3,8)^2=(3,8)^3:(3,8)^2=3,8\)

\(\Rightarrow x=3,8:2=1,9\)

e)

\((\frac{27}{64})^9.x=(\frac{-3}{4})^{32}\)

\(\Leftrightarrow [(\frac{3}{4})^3]^9.x=(\frac{3}{4})^{32}\)

\(\Leftrightarrow (\frac{3}{4})^{27}.x=(\frac{3}{4})^{32}\)

\(\Leftrightarrow x=(\frac{3}{4})^{32}:(\frac{3}{4})^{27}=(\frac{3}{4})^5\)

f)

\(5^{(x+5)(x^2-4)}=1\)

\(\Leftrightarrow (x+5)(x^2-4)=0\)

\(\Leftrightarrow \left[\begin{matrix} x+5=0\\ x^2-4=0\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x+5=0\\ x^2=4=2^2=(-2)^2\end{matrix}\right.\)

\(\Rightarrow \left[\begin{matrix} x=-5\\ x=\pm 2\end{matrix}\right.\)

g)

\((x-2,5)^2=\frac{4}{9}=(\frac{2}{3})^2=(\frac{-2}{3})^2\)

\(\Rightarrow \left[\begin{matrix} x-2,5=\frac{2}{3}\\ x-2,5=\frac{-2}{3}\end{matrix}\right.\Rightarrow \left[\begin{matrix} x=\frac{19}{6}\\ x=\frac{11}{6}\end{matrix}\right.\)

h)

\((2x+\frac{1}{3})^3=\frac{8}{27}=(\frac{2}{3})^3\)

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

a) Lm r nkoa!

b) \(\left(0,25x\right):3=\frac{5}{6}:0,125\)

\(=\left(0,25x\right):3=\frac{20}{3}\)

\(\Rightarrow0,25x=\frac{20}{3}\cdot3=20\)

\(\Rightarrow x=20:0,25=80\)

\(\Rightarrow x=80\)

c) \(0,01:2,5=\left(0,75x\right):0,75\)

\(=\frac{1}{250}=\left(0,75x\right):0,75\)

\(\Rightarrow0,75x=\frac{1}{250}\cdot0,75=\frac{3}{1000}\)

\(\Rightarrow x=\frac{3}{1000}:0,75=\frac{1}{250}\)

\(\Rightarrow x=\frac{1}{250}\)

d) \(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1x\right)\)

\(=\frac{5}{3}=\frac{2}{3}:\left(0,1x\right)\)

\(\Rightarrow0,1x=\frac{2}{3}:\frac{5}{3}=\frac{2}{5}\)

\(\Rightarrow x=\frac{2}{5}:0,1=4\)

\(\Rightarrow4\)

làm 1 bài mẫu nha

a) \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{25}{9}\)

\(\Rightarrow x=\frac{25}{9}:\frac{1}{3}\)

\(\Rightarrow x=\frac{25}{3}\)

các bài sau dễ lắm

a) \(\left(\frac{1}{3}x\right):\frac{2}{3}=1\frac{2}{3}:\frac{2}{5}\)

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{25}{6}\)

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

\(\Rightarrow x=\frac{5}{3}:\frac{1}{3}\)

\(\Rightarrow x=5\)

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

\(\Rightarrow3\left[\left(x+1\right)^2-\frac{x}{2}\right]=4\left(2x-3\right)^2-3\left[\frac{x+1}{4}-\frac{x\left(3-2x\right)}{3}\right]\)

\(\Rightarrow3\left(x+1\right)^2-\frac{3x}{2}=4\left(2x-3\right)^2-\frac{3\left(x+1\right)}{4}+\frac{3x\left(3-2x\right)}{3}\)

\(\Rightarrow36\left(x+1\right)^2-18x=48\left(2x-3\right)^2-9\left(x+1\right)+12x\left(3-2x\right)\)

=> 36.(x² + 2x + 1) - 18x = 48.(4x² - 12x + 9) - 9(x + 1) + 12x(3 - 2x)

=> 36x² + 72x + 36 - 18x - 192x² + 576x - 432 + 9x + 9 - 36x + 24x² = 0

=> -132x² + 603x - 387 = 0

Có: \(\Delta=603^2-4.\left(-387\right)\left(-132\right)=159273\Rightarrow\sqrt{\Delta}=\sqrt{159273}\)

\(\Rightarrow x=\frac{-603+\sqrt{159273}}{-264}\)          hoặc          \(x=\frac{-603-\sqrt{159273}}{-264}\)

Vậy phương trình có 2 nghiệm : x = \(\left\{\frac{-603+\sqrt{159273}}{-264};\frac{-603-\sqrt{159273}}{-264}\right\}\)

Câu này không có nghiệm nguyên nha bạn.

Cảm ơn bn nhìu