x+4.6=18.5的解是（）
x = 18.5 - 4.6 = 13.9
解方程；x-52=15
x = 52 +15 = 67
x÷3.6=1.3
x = 3.6 x 1.3
= 4.68
x-0.75=2.3
x = 0.75 + 2.3
= 3.05
15x=3
x= 5分之1