1206 : x + 342 : x = 6 24 x X - 15 x X = 1980
=> ( 1206 + 342 ) : x = 6 => ( 24 - 15 ) x X = 1980
=> 1548 : x = 6 => 9 x X = 1980
=> x = 1548 : 6 => x = 1980 : 9
=> x = 258 => x = 220
*** ủng hộ mik nha bạn !!!
a)1206/x+342/x=6
1206*1/x+342*1/x=6
(1206+342)*1/x=6
1548*1/x=6
1/x=1548/6
1/x=258
x=1/258
b)24*x-15*x=1980
(24-15)*x=1980
9*x=1980
x=1980/9
x=220