Câu hỏi của Hiệp Đặng

Question

làm hộ mik , mik cần gấp

Thanh Hoàng Thanh · Accepted Answer

Bài 1:$a)\left(x+\dfrac{2}{3}\right)^3=\dfrac{125}{64}.\
\Leftrightarrow\left(x+\dfrac{2}{3}\right)^3=\left(\dfrac{5}{4}\right)^3.\
\Rightarrow x+\dfrac{2}{3}=\dfrac{5}{4}.\
\Leftrightarrow x=\dfrac{7}{12}.$$b)\left(x-\dfrac{1}{2}\right)^3=\dfrac{8}{343}.\\Leftrightarrow\left(x-\dfrac{1}{2}\right)^3=\left(\dfrac{2}{7}\right)
^3.\
\Rightarrow x-\dfrac{1}{2}=\dfrac{2}{7}.\
\Leftrightarrow x=\dfrac{11}{14}.$Bài 2:$a)\left(x-\dfrac{1}{3}\right)^2=\dfrac{25}{9}.\
\Leftrightarrow\left[{}\begin{matrix}\left(x-\dfrac{1}{3}\right)^2=\left(\dfrac{5}{3}\right)^2.\\left(x-\dfrac{1}{3}\right)^2=\left(\dfrac{-5}{3}\right)^2\end{matrix}\right.$$\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{1}{3}=\dfrac{5}{3}.\x-\dfrac{1}{3}=\dfrac{-5}{3}.\end{matrix}\right.$ $\Leftrightarrow\left[{}\begin{matrix}x=2.\x=\dfrac{-4}{3}.\end{matrix}\right.$$b)\left(x-\dfrac{3}{4}\right)^2=\dfrac{49}{16}.\
\Leftrightarrow\left[{}\begin{matrix}\left(x-\dfrac{3}{4}\right)^2=\left(\dfrac{7}{4}\right)^2.\\left(x-\dfrac{3}{4}\right)^2=\left(\dfrac{-7}{4}\right)^2.\end{matrix}\right.$ $\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{7}{4}.\x-\dfrac{3}{4}=\dfrac{-7}{4}.\end{matrix}\right.$ $\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}.\x=-1.\end{matrix}\right.$Câu trả lời: Bài 1:$a)\left(x+\dfrac{2}{3}\right)^3=\dfrac{125}{64}.\
\Leftrightarrow\left(x+\dfrac{2}{3}\right)^3=\left(\dfrac{5}{4}\right)^3.\
\Rightarrow x+\dfrac{2}{3}=\dfrac{5}{4}.\
\Leftrightarrow x=\dfrac{7}{12}.$$b)\left(x-\dfrac{1}{2}\right)^3=\dfrac{8}{343}.\\Leftrightarrow\left(x-\dfrac{1}{2}\right)^3=\left(\dfrac{2}{7}\right)
^3.\
\Rightarrow x-\dfrac{1}{2}=\dfrac{2}{7}.\
\Leftrightarrow x=\dfrac{11}{14}.$Bài 2:$a)\left(x-\dfrac{1}{3}\right)^2=\dfrac{25}{9}.\
\Leftrightarrow\left[{}\begin{matrix}\left(x-\dfrac{1}{3}\right)^2=\left(\dfrac{5}{3}\right)^2.\\left(x-\dfrac{1}{3}\right)^2=\left(\dfrac{-5}{3}\right)^2\end{matrix}\right.$$\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{1}{3}=\dfrac{5}{3}.\x-\dfrac{1}{3}=\dfrac{-5}{3}.\end{matrix}\right.$ $\Leftrightarrow\left[{}\begin{matrix}x=2.\x=\dfrac{-4}{3}.\end{matrix}\right.$$b)\left(x-\dfrac{3}{4}\right)^2=\dfrac{49}{16}.\
\Leftrightarrow\left[{}\begin{matrix}\left(x-\dfrac{3}{4}\right)^2=\left(\dfrac{7}{4}\right)^2.\\left(x-\dfrac{3}{4}\right)^2=\left(\dfrac{-7}{4}\right)^2.\end{matrix}\right.$ $\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{7}{4}.\x-\dfrac{3}{4}=\dfrac{-7}{4}.\end{matrix}\right.$ $\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}.\x=-1.\end{matrix}\right.$

Chúng tôi đề xuất

Tài nguyên

Ứng dụng mobile

Bảng xếp hạng

Các khóa học có thể bạn quan tâm

Yêu cầu VIP