a.x + 4/5 = 3/5 +3/4
<=> x+ 4/5 = 27/20
<=>x =11/20
b,12/5 : x = 9/5 :1/2
<=>12/5 : x = 18/5
<=>x = 2/3
c,7,32 - x = 2,4 + 3,49
<=>7,32 - x = 5,89
<=>x = 3,43
d,17,5 - ( 6 + x ) = 8,74
<=> 11,5 - x = 8,74
<=>x = 2,76
ngu the moi bai toan de the ma khong lam duoc