P/s : mk làm từng phần một
\(\left(\frac{2}{3}\right)^x=\frac{8}{27}=\left(\frac{2}{3}\right)^3\)
=> x = 3
Vậy,........
2)
\(\left(\frac{5}{6}x+\frac{1}{2}\right)^2=\frac{9}{16}=\left(\frac{3}{4}\right)^2\)
\(\frac{5}{6}x+\frac{1}{2}=\frac{3}{4}\)
\(\frac{5}{6}x=\frac{1}{4}\)
\(x=\frac{3}{10}\)
3)
\(\left(\frac{2}{3}x+\frac{5}{6}\right)^3=\frac{-125}{27}=\left(\frac{-5}{3}\right)^3\)
\(\frac{2}{3}x+\frac{5}{6}=-\frac{5}{3}\)
\(\frac{2}{3}x=\frac{-5}{2}\)
\(x=\frac{-15}{4}\)
a,
\(\left(\frac{2}{3}\right)^x=\frac{8}{27}\)
\(\Rightarrow\left(\frac{2}{3}\right)^x=\left(\frac{2}{3}\right)^3\)
\(\Rightarrow x=3\)
b,
\(\left(\frac{5}{6}x+\frac{1}{2}\right)^2=\frac{9}{16}\)
\(\Rightarrow\left(\frac{5}{6}x+\frac{1}{2}\right)^2=\left(\frac{3}{4}\right)^2\)
\(\Rightarrow\frac{5}{6}x+\frac{1}{2}=\frac{3}{4}\)
\(\Rightarrow\frac{5}{6}x=\frac{1}{4}\)
\(\Rightarrow x=\frac{3}{10}\)
c,
\(\left(\frac{2}{3}x+\frac{5}{6}\right)^3=\frac{-125}{27}\)
\(\Rightarrow\left(\frac{2}{3}x+\frac{5}{6}\right)^3=\left(\frac{-5}{3}\right)^3\)
\(\Rightarrow\frac{2}{3}x+\frac{5}{6}=\frac{-5}{3}\)
\(\Rightarrow\frac{2}{3}x=\frac{-5}{2}\)
\(\Rightarrow x=\frac{-15}{4}\)
a,x=3
b,x=\(\frac{3}{10}\)
c,\(-\frac{15}{4}\)
