TH1 : 17 + m
<=> \(\frac{17+m}{18-m}=\frac{3}{4}\)
=> 4 ( 17 + m ) = 3 ( 18 - m )
68 + 4m = 54 - 3m
4m + 3m = 54 - 68
7m = -14
m = -2
TH2 : 17 - m
<=> \(\frac{17-m}{18+m}=\frac{3}{4}\)
=> 68 - 4m = 54 + 3m
68 - 54 = 3m + 4m
14 = 7m
m = 2
Vậy,...........