45+78-x=64
78-x=64-45
78-x=19
x=78-19
x=59
46-x+10=15.5
46-x= 15.5-10
46-x=5.5
x=46-5.5
x=40.5
1.47÷x=2.1
x=1.47÷2.1
x=0.7