\(\left[\frac{4}{7}-\frac{1}{2}.x\right]^3=2^3\)
\(\Rightarrow\frac{4}{7}-\frac{1}{2}.x=2\)
\(\frac{1}{2}.x=-\frac{10}{7}\)
\(x=-\frac{20}{7}\)
làm phiền cho mk hỏi câu này với nếu ko biết thì thôi:so sánh:\(\frac{2^{23}+1}{2^{25}+1}va\frac{2^{25}+1}{2^{27}+1}\)
Ta thấy: \(\left(2^2-1\right)\left(2^{50}-1\right)>0\)
\(\Rightarrow2^{52}+1-2^{50}-4>0\)
\(\Rightarrow2^{52}+1>2^{50}+4\)
\(\Rightarrow2^{52}+1>\left(2^{48}+1\right).2^2\)
\(\Rightarrow\frac{2^{52}+1}{2^{27}}>\frac{\left(2^{48}+1\right).2^2}{2^{27}}\)
\(\Leftrightarrow2^{25}+\frac{1}{2^{27}}>2^{23}+\frac{1}{2^{27}}\)
\(\Leftrightarrow2^{25}+\frac{1}{2^{27}}+1>2^{23}+\frac{1}{2^{27}}+1\)
