Đáp án:
$a)x=4040-2\sqrt{2019}$
$b)$\(\left[ \begin{array}{l}x=52\\x=-49\end{array} \right.\)
Giải thích các bước giải:
$a)\sqrt{x-2020}=\sqrt{2019}-1$ $ĐK: x≥2020$
$⇔x-2020=2019+1-2.\sqrt{2019}$
$⇔x=4040-2\sqrt{2019}(TM)$
$b)20\sqrt{4x^2-12x+9}=2020$
$⇔20.\sqrt{(2x-3)^2}=2020$
$⇔|2x-3|=101$
$⇔$\(\left[ \begin{array}{l}2x-3=101\\2x-3=-101\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}2x=104\\2x=-98\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}x=52\\x=-49\end{array} \right.\)
