(1)7.2+x=9.6,
7.2+x-7.2=9.6-7.2,
x=2.4;
(2)7x=6.3,
7x÷7=6.3÷7,
x=0.9;
(3)x÷5=12.5,
x÷5×5=12.5×5,
x=62.5.