(1)X-35=60
X-35+35=60○□
X=□
(2)X+17=57
X+17-17=57○□
x=□
(3)x÷7=105
X÷7×7=105○□
X=□
(4)0.9X=6.3
0.9X÷0.9=6.3○□
x=□
(1)X-35=60,
X-35+35=60+35,
X=95;
(2)X+17=57,
X+17-17=57-17,
X=40;
(3)X÷7=105,
X÷7×7=105×7,
X=735;
(4)0.9X=6.3,
0.9X÷0.9=6.3÷0.9,
X=7.
故答案为:+,35,95,-,17,40,×,7,735,÷,0.9,7.