Tìm x, biết:
a) \(\left(\dfrac{1}{16}\right)^x\) = \(\left(\dfrac{1}{2}\right)^{10}\) b)\(\left(-\dfrac{8}{13}\right)^x\) = \(\dfrac{64}{169}\) c)\(\left(\dfrac{4}{9}\right)^{x+1}\) = \(\left(\dfrac{8}{27}\right)^6\) d) \(\left(\dfrac{1}{16}\right)^{x+2}\) = \(\left(\dfrac{1}{32}\right)^6\)
\(\left(\dfrac{1}{16}\right)^x=\left(\dfrac{1}{2}\right)^{10}\Leftrightarrow\left(\dfrac{1}{2}\right)^{4.x}=\left(\dfrac{1}{2}\right)^{10}\)
\(\Leftrightarrow4x=10\Leftrightarrow x=2,5\)
ý b tương tự x=2 nhé
chữa thêm cho bạn ý d nhé:
\(\left(\dfrac{1}{16}\right)^{x+2}=\left(\dfrac{1}{32}\right)^6\Leftrightarrow\left(\dfrac{1}{2}\right)^{4.\left(x+2\right)}=\left(\dfrac{1}{2}\right)^{6.5}\)
\(\Leftrightarrow4.\left(x+2\right)=30\Leftrightarrow4x=22\Leftrightarrow x=5,5\)