Question

b) x= 7¹⁶-3 / 7¹⁶+1 và y= 7¹⁷-3 / 7¹⁷+1 

mình đag cần rất gấp

Answer 1

Ta có: x = \(\frac{7^{16}-3}{7^{16}+1}=\frac{7^{16}+1-4}{7^{16}+1}=1-\frac{4}{7^{16}+1}\)

y = \(\frac{7^{17}-3}{7^{17}+1}=\frac{7^{17}+1-4}{7^{17}+1}=1-\frac{4}{7^{17}+1}\)

Do \(7^{16}+1< 7^{17}+1\) => \(\frac{4}{7^{16}+1}>\frac{4}{7^{17}+1}\) => \(-\frac{4}{7^{16}+1}< -\frac{4}{7^{17}+1}\)

=> \(1-\frac{4}{7^{16}+1}< 1-\frac{4}{7^{17}+1}\) => x < y

Answer 2

Trả lời:

\(x=\frac{7^{16}-3}{7^{16}+1}=\frac{7^{16}+1-4}{7^{16}+1}=\frac{7^{16}+1}{7^{16}+1}-\frac{4}{7^{16}+1}=1-\frac{4}{7^{16}+1}\)

\(y=\frac{7^{17}-3}{7^{17}+1}=\frac{7^{17}+1-4}{7^{17}+1}=\frac{7^{17}+1}{7^{17}+1}-\frac{4}{7^{17}+1}=1-\frac{4}{7^{17}+1}\)

Ta có: \(7^{16}< 7^{17}\)

\(\Leftrightarrow7^{16}+1< 7^{17}+1\)

\(\Leftrightarrow\frac{4}{7^{16}+1}>\frac{4}{7^{17}+1}\)

\(\Leftrightarrow-\frac{4}{7^{16}+1}< -\frac{4}{7^{17}+1}\)

\(\Leftrightarrow1-\frac{4}{7^{16}+1}< 1-\frac{4}{7^{17}+1}\)

\(\Leftrightarrow x< y\)

Vậy x < y