Câu hỏi của Nguyễn Thùy Dương

Question

Tìm x:$x:\left(-\frac{1}{3}\right)^3=-\frac{1}{3}$$\left(\frac{4}{5}\right)^5.x=\left(\frac{4}{5}\right)^7$$\left(x+\frac{1}{2}\right)^2=\frac{1}{16}$$\left(3x+1\right)^3=-27$

Huỳnh Quang Sang · Accepted Answer

$\frac{x}{\left(-\frac{1}{3}\right)^3}=-\frac{1}{3}\Rightarrow x=\left(-\frac{1}{3}\right)\left(-\frac{1}{3}\right)^3=\left(-\frac{1}{3}\right)^4$$\left(\frac{4}{5}\right)^5\cdot x=\left(\frac{4}{5}\right)^7$=> $x=\frac{\left(\frac{4}{5}\right)^7}{\left(\frac{4}{5}\right)^5}=\left(\frac{4}{5}\right)^2=\frac{16}{25}$$\left(x+\frac{1}{2}\right)^2=\frac{1}{16}=\left(\pm\frac{1}{4}\right)^2$=> $\orbr{\begin{cases}x+\frac{1}{2}=\frac{1}{4}\x+\frac{1}{2}=-\frac{1}{4}\end{cases}}\Rightarrow\orbr{\begin{cases}x=-\frac{1}{4}\x=-\frac{3}{4}\end{cases}}$(3x + 1)3 = -27 => (3x + 1)3 = (-3)3 => 3x + 1 = -3 => 3x = -4 => x = -4/3Câu trả lời: $\frac{x}{\left(-\frac{1}{3}\right)^3}=-\frac{1}{3}\Rightarrow x=\left(-\frac{1}{3}\right)\left(-\frac{1}{3}\right)^3=\left(-\frac{1}{3}\right)^4$$\left(\frac{4}{5}\right)^5\cdot x=\left(\frac{4}{5}\right)^7$=> $x=\frac{\left(\frac{4}{5}\right)^7}{\left(\frac{4}{5}\right)^5}=\left(\frac{4}{5}\right)^2=\frac{16}{25}$$\left(x+\frac{1}{2}\right)^2=\frac{1}{16}=\left(\pm\frac{1}{4}\right)^2$=> $\orbr{\begin{cases}x+\frac{1}{2}=\frac{1}{4}\x+\frac{1}{2}=-\frac{1}{4}\end{cases}}\Rightarrow\orbr{\begin{cases}x=-\frac{1}{4}\x=-\frac{3}{4}\end{cases}}$(3x + 1)3 = -27 => (3x + 1)3 = (-3)3 => 3x + 1 = -3 => 3x = -4 => x = -4/3

ᵛᶰシHắ¢ღHσàиɢღTнιêиღуυм★彡 · Answer

a)$x:\left(\frac{-1}{3}\right)^3=\frac{-1}{3}$$=>x:\frac{-1}{27}=\frac{-1}{3}$$=>x=\frac{-1}{3}.\frac{-1}{27}=>x=\frac{1}{81}$b) $\left(\frac{4}{5}\right)^5.x=\left(\frac{4}{5}\right)^7$$=>x=\left(\frac{4}{5}\right)^7:\left(\frac{4}{5}\right)^5=>x=\left(\frac{4}{5}\right)^2=\frac{16}{25}$c)$\left(x+\frac{1}{2}\right)^2=\frac{1}{16}$$=>\orbr{\begin{cases}\left(x+\frac{1}{2}\right)^2=\left(\frac{1}{4}\right)^2\\left(x+\frac{1}{2}\right)^2=\left(\frac{-1}{4}\right)^2\end{cases}}$$=>\orbr{\begin{cases}x+\frac{1}{2}=\frac{1}{4}\x+\frac{1}{2}=\frac{-1}{4}\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{-1}{4}\x=-1\end{cases}}}$d|) $\left(3x+1\right)^3=-27$$=>\left(3x+1\right)^3=\left(-3\right)^3$$=>3x+1=-3$$=>3x=-4=>x=\frac{-4}{3}$cậu có thể tham khảo bài làm trên đây ạ, chúc cậu học tốt:>Câu trả lời: a)$x:\left(\frac{-1}{3}\right)^3=\frac{-1}{3}$$=>x:\frac{-1}{27}=\frac{-1}{3}$$=>x=\frac{-1}{3}.\frac{-1}{27}=>x=\frac{1}{81}$b) $\left(\frac{4}{5}\right)^5.x=\left(\frac{4}{5}\right)^7$$=>x=\left(\frac{4}{5}\right)^7:\left(\frac{4}{5}\right)^5=>x=\left(\frac{4}{5}\right)^2=\frac{16}{25}$c)$\left(x+\frac{1}{2}\right)^2=\frac{1}{16}$$=>\orbr{\begin{cases}\left(x+\frac{1}{2}\right)^2=\left(\frac{1}{4}\right)^2\\left(x+\frac{1}{2}\right)^2=\left(\frac{-1}{4}\right)^2\end{cases}}$$=>\orbr{\begin{cases}x+\frac{1}{2}=\frac{1}{4}\x+\frac{1}{2}=\frac{-1}{4}\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{-1}{4}\x=-1\end{cases}}}$d|) $\left(3x+1\right)^3=-27$$=>\left(3x+1\right)^3=\left(-3\right)^3$$=>3x+1=-3$$=>3x=-4=>x=\frac{-4}{3}$cậu có thể tham khảo bài làm trên đây ạ, chúc cậu học tốt:>

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