Question

Tìm x biết
a. \(x:\left(\dfrac{-3}{5}\right)^2=\dfrac{-3}{5}\)
b.\(\left(\dfrac{-1}{3}\right)^3.x=\dfrac{1}{81}\)

c.\(\left(2x^2\right)=16\)

Answer 1

a,\(x:\left(\dfrac{-3}{5}\right)^2=\dfrac{-3}{5}\)

\(\Leftrightarrow x=\dfrac{-3}{5}.\dfrac{9}{25}\Leftrightarrow x=\dfrac{-27}{125}\)

b,\(\left(\dfrac{-1}{3}\right)^3.x=\dfrac{1}{81}\)

\(\Leftrightarrow x=.\dfrac{1}{81}:\left(\dfrac{-1}{27}\right)\Leftrightarrow x=\dfrac{-1}{3}\)

c,(2x²)=16\(\Leftrightarrow\)x²=8\(\Leftrightarrow\)x=\(,\sqrt{8}\)

Answer 2

Giải:

a. \(x:\left(\dfrac{-3}{5}\right)^2=\dfrac{-3}{5}\)

\(\Rightarrow x=\left(\dfrac{-3}{5}\right)^2.\dfrac{-3}{5}\)

\(\Rightarrow x=\left(\dfrac{-3}{5}\right)^3\)

\(\Rightarrow x=\dfrac{-27}{125}\)

Vậy.................

b.\(\left(\dfrac{-1}{3}\right)^3.x=\dfrac{1}{81}\)

\(\Rightarrow x=\dfrac{1}{81}:\left(\dfrac{-1}{3}\right)^3\)

\(\Rightarrow x=\dfrac{1}{81}:\dfrac{-1}{27}\)

\(\Rightarrow x=\dfrac{1}{81}.\dfrac{-27}{1}\)

\(\Rightarrow x=\dfrac{1}{3}.\dfrac{-1}{1}\)

\(\Rightarrow x=\dfrac{-1}{3}\)

vậy................

c.\(\left(2x^2\right)=16\)

\(\Rightarrow2x=\sqrt{16}=4\)

\(\Rightarrow x=4:2\)

\(\Rightarrow x=2\)

vậy....................