Question

So Sánh :( Ko quy đồng nhé)

A= -7/10²⁰¹⁶+ -15/10²⁰¹⁷

^B= -15/10²⁰¹⁶+-7/10²⁰¹⁷

Answer 1

Ta có:

\(A-B=-\dfrac{7}{10^{2016}}-\dfrac{15}{10^{2017}}+\dfrac{15}{10^{2016}}+\dfrac{7}{10^{2017}}\)

\(=\left(\dfrac{15}{10^{2016}}-\dfrac{7}{10^{2016}}\right)+\left(\dfrac{7}{10^{2017}}-\dfrac{15}{10^{2017}}\right)\)

\(=\dfrac{9}{10^{2016}}-\dfrac{9}{10^{2017}}=9\left(\dfrac{1}{10^{2016}}-\dfrac{1}{10^{2017}}\right)>0\)

Vậy A > B

Answer 2

\(A=\dfrac{-7}{10^{2016}}+\dfrac{-15}{10^{2017}}=\dfrac{-7}{10^{2016}}+\dfrac{-8}{10^{2017}}+\dfrac{-7}{10^{2017}}\\ B=\dfrac{-15}{10^{2016}}+\dfrac{-7}{10^{2017}}=\dfrac{-7}{10^{2016}}+\dfrac{-8}{10^{2016}}+\dfrac{-7}{10^{2017}}\)

Vì \(\dfrac{-8}{10^{2017}}>\dfrac{-8}{10^{2016}}\) nên \(A>B\)