1-1/2*□=9/70
(1/3÷7/9-3/10)÷(1-1/2*□)=1
1-1/2*□=1/3÷7/9-3/10
1-1/2*□=1/3×9/7-3/10
1-1/2*□=3/7-3/10
1-1/2*□=9/70
2-□=9/35
□=2-9/35
□=61/35