1)Tìm x biết:
A)\(\left(\dfrac{2}{5}-3x\right)^2=\dfrac{9}{25}\)
B)\(\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)^5=\dfrac{1}{243}\)
2)So sánh:
A)\(5^{222}và\)\(2^{555}\)
B)\(3^{48}và4^{36}\)
1/ a/ \(\left(\dfrac{2}{5}-3x\right)^2=\dfrac{9}{25}\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(\dfrac{2}{5}-3x\right)^2=\left(\dfrac{3}{5}\right)^2\\\left(\dfrac{2}{5}-3x\right)^2=\left(\dfrac{-3}{5}\right)^2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{2}{5}-3x=\dfrac{3}{5}\\\dfrac{2}{5}-3x=-\dfrac{3}{5}\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}3x=-\dfrac{1}{5}\\3x=1\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-1}{15}\\x=\dfrac{1}{3}\end{matrix}\right.\)
Vậy --...
b/ \(\left(\dfrac{2}{3}x-\dfrac{1}{3}\right)^5=\dfrac{1}{243}\)
\(\Leftrightarrow\left(\dfrac{2}{3}x-\dfrac{1}{5}\right)^5=\left(\dfrac{1}{3}\right)^5\)
\(\Leftrightarrow\dfrac{2}{3}x-\dfrac{1}{5}=\dfrac{1}{3}\)
\(\Leftrightarrow\dfrac{2}{3}x=\dfrac{8}{15}\)
\(\Leftrightarrow x=\dfrac{24}{30}\)
Vậy -
Cho biết:
13+23+33+...+103=3025
Tính: a)A=23+43+63+...+203
b) B= 0,53+13+1,53+...+53
Tim tat ca cac so tu nhien n sao cho
a,23.32\(\ge\)2n>16
b,25<5n<625
Tính giá trị biểu thức
\(A=\left(\dfrac{ab}{2}-\dfrac{6ab}{7}\right):\dfrac{5b^2}{14}biết;a=\dfrac{2007}{2010},b=\dfrac{2015}{2016}\)
rút gọn A= 1+22+24+...+250
Chứng minh 810-89-88 chia hết cho 11
Tìm x:
(2-1)x+2=(x-1)x+4
Giải giúp mik vs
Tính:
\(\left(\dfrac{1}{10}\right)^{10}.\left(\dfrac{1}{2}\right)^{50}\)
tìm x biết
a) \(\dfrac{2}{5}-\left(\dfrac{1}{10}-x\right)=\left(\dfrac{-2}{5}-\dfrac{1}{2}\right)^2\)
b) \(\dfrac{2}{5}-\dfrac{3}{5}\left(x-2\right)=\left(\dfrac{-1}{2}\right)^3-\left(\dfrac{3}{4}\right)^3.\left(-2\right)^2\)
1 tính
a. \((\left|-5\right|7^4+3^2.2\dfrac{2}{5}):(7^5.125.7^3.50)\)
b. \((\dfrac{3^2}{9}.\dfrac{3^3}{81})^{12}:(\dfrac{3^6}{81^2})^{10}\)
c. \([(\dfrac{1}{2})^2.(\dfrac{1}{3})^4.\dfrac{2}{7}]:\left(\dfrac{1}{3}\right)^{-2}.\dfrac{-2^2}{7}\)
\(8^x\): \(4^x\)=16
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến