Question

z=6x+px+2, solve for x

Answer 1

z = 6x + px + 2
z - 2 = 6x + px (take the 2 to the left hand side)
z - 2 = x(6 + p) (Factorise the x out)
x = z - 2 / 6 + p (Divide z - 2 by 6 + p to get x on its own)

Answer 2

x = (z - 2) / (6 + p)

Those brackets are essential here.