b. (2x-1)4 = 81
(2x-1)4 = 34
=> 2x-1 = 3
2x = 3 + 1
2x = 4
x = 4 : 2
x = 2
♥๖ۣۜShino♥Ko bt thì đừng trả lời \(\left(2x-1\right)^4=81\)
\(\Leftrightarrow\left(2x-1\right)^4=\left(\pm3\right)^4\)
\(\Leftrightarrow\orbr{\begin{cases}2x-1=3\\2x-1=-3\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-1\end{cases}}\)
Vậy x = 2 hoặc x = -1
c. (3x+1)3 = \(\frac{1}{64}\)
(3x+1)3 = \(\left(\frac{1}{4}\right)^3\)
=> 3x+1 = \(\frac{1}{4}\)
3x = \(\frac{1}{4}-1\)
3x = \(\frac{1}{4}-\frac{4}{4}\)
3x = \(-\frac{3}{4}\)
x = \(-\frac{3}{4}:3\)
x = \(-\frac{3}{4}\) \(.\)\(\frac{1}{3}\)
x = \(-\frac{1}{4}\)
Đừng gắt thế chứ, kiệt.
Sao vô tình vậy.
Kệ shino đi, ít gì thì bạn ấy cũng mắt công làm mà.
a) \(\left|x-1\right|-\left(\frac{1}{2}\right)^2=1\)
\(\Leftrightarrow\left|x-1\right|-\frac{1}{4}=1\)
\(\Leftrightarrow\left|x-1\right|=1+\frac{1}{4}\)
\(\Leftrightarrow x-1=\pm\frac{5}{4}\)
\(\Leftrightarrow\orbr{\begin{cases}x-1=-\frac{5}{4}\\x-1=\frac{5}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{4}\\x=\frac{9}{4}\end{cases}}\)
b) \(\left(2x-1\right)^4=81\)
\(\Leftrightarrow2x-1=\left(\pm3\right)^4\)
\(\Leftrightarrow\orbr{\begin{cases}2x-1=-3\\2x-1=3\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-2\\x=2\end{cases}}\)
c) \(\left(3x+1\right)^3=\frac{1}{64}\)
\(\Leftrightarrow3x+1=\left(\frac{1}{4}\right)^3\)
\(\Leftrightarrow3x=\frac{1}{4}-1\)
\(\Leftrightarrow3x=-\frac{3}{4}\)
\(\Leftrightarrow x=-\frac{3}{4}:3\)
\(\Leftrightarrow x=-\frac{1}{4}\)
Câu b) \(\orbr{\begin{cases}x=-1\\x=2\end{cases}}\)
Còn lại Tham khảo bạn KẻKhờ
a) \(\left|x-1\right|-\left(\frac{1}{2}\right)^2=1\)
\(\Leftrightarrow\left|x-1\right|-\frac{1}{4}=1\)
\(\Leftrightarrow\left|x-1\right|=1+\frac{1}{4}=\frac{5}{4}\)
\(\Leftrightarrow\orbr{\begin{cases}x-1=\frac{5}{4}\\x-1=\frac{-5}{4}\end{cases}}\) \(\Leftrightarrow\orbr{\begin{cases}x=\frac{9}{4}\\x=-\frac{1}{4}\end{cases}}\)
b. \(\left(2x-1\right)^4=81\)
\(\Leftrightarrow\left(2x-1\right)^4=\left(\pm3\right)^4\)
\(\Leftrightarrow\orbr{\begin{cases}2x-1=3\\2x-1=-3\end{cases}}\) \(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)
1÷0=0 2÷0=0 3÷0=0 4÷0=0