Toán Lớp 9: so sánh
x=2020a và y=2020+a (với x,y là tham số)
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Toán Lớp 9: so sánh
x=2020a và y=2020+a (với x,y là tham số)
Comments ( 1 )
x = y\,khi:a = \dfrac{{2020}}{{2019}}\\
x > y\,khi:a > \dfrac{{2020}}{{2019}}\\
x < y\,khi:a < \dfrac{{2020}}{{2019}}
\end{array} \right.$
+ Khi:x = y\\
\Leftrightarrow 2020.a = 2020 + a\\
\Leftrightarrow 2019.a = 2020\\
\Leftrightarrow a = \dfrac{{2020}}{{2019}}\\
+ Khi:x > y\\
\Leftrightarrow 2020a > 2020 + a\\
\Leftrightarrow 2019a > 2020\\
\Leftrightarrow a > \dfrac{{2020}}{{2019}}\\
+ Khi:x < y\\
\Leftrightarrow a < \dfrac{{2020}}{{2019}}\\
Vay\,\left\{ \begin{array}{l}
x = y\,khi:a = \dfrac{{2020}}{{2019}}\\
x > y\,khi:a > \dfrac{{2020}}{{2019}}\\
x < y\,khi:a < \dfrac{{2020}}{{2019}}
\end{array} \right.
\end{array}$