a) x = 3y+6
3y = x-6
divide both sides by 3.
y = (x/3) -2
b) x = 5y-10
5y = x+10
divide both sides by 5.
y = (x/5) +2
c) x = y^2
square root both sides.
y = sqrt(x)
d) x = 2y^2 -4
x+4 = 2y^2
divide both sides by 2.
(x/2) +2 = y^2
square root both sides.
y = sqrt((x/2)+2)
e) x = (y-5)^2
square root both sides.
sqrt(x) = y-5
y = sqrt(x) +5