Question

Tìm x

a) (2x+3)²=9/25

b) (3x-1)³=-1/27

Answer 1

a) \(\left(2x+3\right)^2=\frac{9}{25}\)

\(\Rightarrow\left(2x+3\right)^2=\left(\frac{3}{5}\right)^2\) hoặc \(\left(2x+3\right)^2=\left(-\frac{3}{5}\right)^2\)

\(\Rightarrow2x+3=\frac{3}{5}\) hoặc \(2x+3=-\frac{3}{5}\)

\(\Rightarrow2x=-\frac{12}{5}\) hoặc \(2x=-\frac{18}{5}\)

\(\Rightarrow x=-\frac{6}{5}\) hoặc \(x=-\frac{9}{5}\)

Vậy.......

b) \(\left(3x-1\right)^3=\frac{1}{27}\)

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

\(\Rightarrow3x-1=\frac{1}{3}\)

\(\Rightarrow3x=\frac{4}{3}\)

\(\Rightarrow x=\frac{4}{9}\)

Vậy.......

Answer 2

a) (2x+3)²=\(\frac{9}{25}\)

2x+3=\(\sqrt{\frac{9}{25}}\)=\(\frac{3}{5}\)

2x=\(\frac{-12}{5}\)

x=\(\frac{-6}{5}\)

b) (3x-1)³=\(\frac{-1}{27}\)

3x-1=\(\frac{-1}{3}\)

3x=\(\frac{2}{3}\)

x=\(\frac{2}{9}\)

Answer 3

a) ( 2x + 3 )² = \(\frac{9}{25}\)

\(\Rightarrow2x+3=\frac{3}{5}\)hoặc \(-\frac{3}{5}\)

\(\Rightarrow2x=-\frac{12}{5}\)hoặc \(-\frac{18}{5}\)

\(\Rightarrow x=-\frac{6}{5}\)hoặc\(-\frac{9}{5}\)

b) ( 3x - 1)³ = \(-\frac{1}{27}\)

\(\Rightarrow3x-1=-\frac{1}{3}\)

\(\Rightarrow3x=\frac{2}{3}\)

\(\Rightarrow x=\frac{2}{9}\)