Đáp án:
$2012$
Giải thích các bước giải:
Ta có:
$\begin{array}{l}\quad 2x - y = 3\\
\to y = 2x - 3\\
\to 2^{\displaystyle{y}} = 2^{\displaystyle{2x-3}}\\
\to 2^{\displaystyle{y}} = \dfrac{2^{\displaystyle{2x}}}{2^3}\\
\to 2^{\displaystyle{y}} = \dfrac{4^{\displaystyle{x}}}{8}\end{array}$
Do đó:
$2020 - \dfrac{4^{\displaystyle{x}}}{2^y}$
$= 2020 - \dfrac{4^{\displaystyle{x}}}{\dfrac{4^{\displaystyle{x}}}{8}}$
$= 2020 - 8$
$= 2012$
