Sửa đề: \(\left(\dfrac{1}{9}\right)^x\cdot27^{2x}=\left(-9\right)^4\)
\(\Leftrightarrow\left(\dfrac{1}{3}\right)^{2x}\cdot27^{2x}=9^4\)
=>92x=94
=>2x=4
hay x=2
Tìm \(x\), biết :
a) \(\left(2x+3\right)^2=\dfrac{9}{121}\)
b) \(\left(3x-1\right)^3=-\dfrac{8}{27}\)
Rút gọn:
a) \(\dfrac{2^{19}\cdot27^3+15\cdot4^9\cdot9^4}{6^9\cdot2^{10}+2^{10}}\)
b) \(\dfrac{\left(-\dfrac{1}{2}\right)^3-\left(\dfrac{3}{4}\right)^3\cdot\left(-2\right)^2}{2\cdot\left(-1\right)+\left(\dfrac{3}{4}\right)^2-\left(\dfrac{3}{8}\right)}\)
\(\left(2x+3\right)^2=\frac{9}{121}\\ \left(3x-1\right)^3=-\frac{8}{27}\)
tính
a) \(\left(\dfrac{1}{3}\right)^4.\left(\dfrac{-9}{6}\right)^6\)
b) \(\left(\dfrac{-31}{8}\right)^3.\left(\dfrac{-32}{31}\right)^4\)
1: Tính : \(\dfrac{\left(\dfrac{2}{5}\right)^7.5^7+\left(\dfrac{9}{4}\right)^3:\left(\dfrac{3}{16}\right)^3}{2^7.5^2+512}\) 2 . Tìm x biết :\(\left(5.x+1\right)^2=\dfrac{36}{49}\)
BT4:Tìm x, biết:
a) \(x\div\left(\dfrac{3}{4}\right)^3=\left(\dfrac{3}{4}\right)^2\)
b) \(\left(\dfrac{2}{5}\right)^5\div x=\left(\dfrac{2}{5}\right)^8\)
Trong vở bài tập của bạn Dũng có bài làm sau :
a) \(\left(-5\right)^2.\left(-5\right)^3=\left(-5\right)^6\)
b) \(\left(0,75\right)^3:0,75=\left(0,75\right)^2\)
c) \(\left(0,2\right)^{10}:\left(0,2\right)^5=\left(0,2\right)^2\)
d) \(\left[\left(-\dfrac{1}{7}\right)^2\right]^4=\left(-\dfrac{1}{7}\right)^6\)
e) \(\dfrac{50^3}{125}=\dfrac{50^3}{5^3}=\left(\dfrac{50}{5}\right)^3=10^3=1000\)
Hãy kiểm tra lại các đáp số và sửa lại chỗ sai (nếu có)
f) \(\dfrac{8^{10}}{4^8}=\left(\dfrac{8}{4}\right)^{10-8}=2^2\)
Tìm x, biết:
a) x : \(\left(\dfrac{3}{4}\right)^3\)= \(\left(\dfrac{3}{4}\right)^2\) b) \(\left(\dfrac{2}{5}\right)^5\). x = \(\left(\dfrac{2}{5}\right)^8\)
tìm x biết
a) \(\dfrac{2}{5}-\left(\dfrac{1}{10}-x\right)=\left(\dfrac{-2}{5}-\dfrac{1}{2}\right)^2\)
b) \(\dfrac{2}{5}-\dfrac{3}{5}\left(x-2\right)=\left(\dfrac{-1}{2}\right)^3-\left(\dfrac{3}{4}\right)^3.\left(-2\right)^2\)
