How do i include an

See this solution http://www.fixya.com/support/t663157-calculate_equation,

also in the case of your example:

4y=2x4 (4 times y = 2 times x times 4, moving the 4 over makes it divide by 4)

y=2x4 (the 4's cancel out, 4 divided by 4 = 1, 1 times anything is the same)
4

so y=2x (if we move x over it becomes divide by)

so y=2 (y diveided by x = 2 is as far as you can go)
x