Rewriting formula

This task is about re-arranging equations to make x the subject.
Re-write each of the formulae below to make x the subject.
 
a)
y = x + 4
 
x = ____________________
 
b)
y = 3x
 
x = ____________________
 
c)
y = x5
 
x = ____________________
 
d) 
y = 5x2
 
x = ____________________
 
e)
y = 2x - 1
 
x = ____________________