Đáp án:
$29 - ( 209/10 × x - 80 ) ÷ 2010/29 = 0$
$( 209/10 × x - 80 ) × 2010/29 = 29 - 0$
$( 209/10 × x - 80 ) ÷ 2010/29 = 29$
$( 20,9 × x -80 ) = 29 × 2010/ 29$
$( 20,9 × x -80 ) = 2010$
$20,9 × x = 2010 + 80$
$20,9 × x = 2090$
$x = 2090 ÷ 20,9$
$x = 100$