1)1/2x+1/3x=3
3/6x+2/6x=3
5/6x=3
x=3*6/5 =18/5=3.6
2) 2/7÷(2/5+1/3)
=2/7÷(6/15+5/15)
=2/7÷11/15
=2/7*15/11
=30/77
3) 2-7/12×9/14 (7和14约分,9和12约分)
=2-3/8
=13/8
1)1/2x+1/3x=3
3/6x+2/6x=3
5/6x=3
x=3*6/5 =18/5=3.6
2) 2/7÷(2/5+1/3)
=2/7÷(6/15+5/15)
=2/7÷11/15
=2/7*15/11
=30/77
3) 2-7/12×9/14 (7和14约分,9和12约分)
=2-3/8
=13/8