=>x+2/7=17/12-10/12=7/12
=>x=7/12-2/7=49/84-24/84=25/84
1: tìm x
a) x + 2/7 = 17/12 - 5/6
b) x - 3/5 = 13/14 - 2/7
c) 11/18 - x = 7/12 - 5/18
2: tính bằng 2 cách.
a) ( 6/11 + 5/11 ) x 3/7
b) 3/5 x 7/9 - 3/5 x 2/9
c) ( 6/7 - 4/7 ) : 2/5
d) 8/15 : 2/11 + 7/15 : 2/11